Tang Xiyang graduated from Beijing Normal University and then worked as a journalist for a Beijing newspaper from 1952 - 1957. Condemned as a rightist in 1957, Tang was forced to work in factories and on farms in the Beijing area until his rehabilitation in 1979. During the Cultural Revolution, his first wife, Beijing Middle School No. 52 teacher Zheng Zhaonan (郑兆南), involved in factional struggles at her school, was beaten severely, humiliated and cruelly mistreated for 47 days by the middle school's Red Guards for being anti-Party and counter-revolutionary as a result. She was refused medical care and died of her injuries. Her refusal to denounce her husband Tang Xiyang as a rightist, and her landlord family background were likely important reasons for the ferocity of the attacks on her. Zheng Zhaonan's posthumously published letter explaining her political position became well known.
In passages censored from "A Green World Tour" Tang Xiyang discussed his experience of the Anti-Rightist Movement and the Cultural Revolution during with Americans during his visit to the United States:
These were all ‘Cultural Revolution’ matters. My thoughts then turned to the earlier anti-Rightist campaign and I told me listeners about that too. “In June 1957 the staff of the Beijing Daily was called to the fourth-floor auditorium to attend a general meeting criticizing Liu Binyan, then with China Youth Daily. A colleague of his, Qi Xueyi, opposed the meeting, so to show his support for Liu, he jumped from the auditorium window into the hutong below and was killed.
Since I had already been labeled a Rightist, I was not allowed to attend this meeting, but my wife, Zheng Zhaonan, who also at that time worked for Beijing Daily, did attend. Like everyone else, she looked out the window where Qi had jumped, and perhaps thinking of me and our situation, stayed there for a long moment. This was noticed and reported to the newspaper’s leaders, who immediately called another meeting, at which Qi was first criticized. His deed was called counterrevolutionary; he had substituted for a Rightist; it was a bad act to try to stop the meeting; if he could kill himself, he could kill anyone, so he was the worst kind of class enemy. Then Zheng was criticized for feeling sorry for him; she was the same sort of ‘raccoon dog’, the epigram about the fox that was sorry after the rabbit died because now it had nothing to eat was used to describe her; she was criticized for even thinking about her husband.
That night Zheng cried bitterly and said that she was afraid. It would never have occurred to me that ten years later it would be she who was killed and not I. She was only one of many. The statistics were later printed in a book: In Beijing, between August 19 and September 30, 1966, over 1,700 people were killed; 33,600 houses were searched and the residents’ property was confiscated; 85,000 people belonging to ‘bad’ categories were exiled to distant parts of the country. My wife was killed during those forty days too. Human nature, human sympathy, human rights, human dignity, human value – the most essential human qualities – were all suppressed during the so-called Cultural Revolution. It was the twentieth century’s greatest world tragedy. I have tried to forget but I cannot.
Did you think of committing suicide, especially after your wife was killed?
How could I? I had two daughters, the elder one twelve years old, the younger one only six. How could they bear losing their father just after losing their mother? Yes, if it hadn’t been for them, I would have committed suicide ten times over.
You were imprisoned, weren’t you?
Yes, but in the beginning I was permitted to go home at night. I had to write out my ‘confessions’ under ten at night and be out sweeping the streets by five in the morning, so it was about ten-thirty when I got home and only 4:30 when I left. The children had already fallen asleep when I arrived and had not yet awakened when I left, so my eldest daughter and I had to write notes to each other in a diary. I told them to diligently study Chairman Mao Zedong’s quotations, to struggle against selfish motives, to criticize revisionism, and to save their small change and to keep on good terms with the neighbor’s children. When my house was later searched and all my possessions seized and broken, only the diary survived, which I now keep as a treasured document.
In 1980 he became founded Great Nature magazine, and later he wrote the book A Green World Tour, which has become important for China's younger environmentalists. Tang met his second wife, Marsha Marks of New York, in 1981 and began a long collaboration which ended with her death in July 1996.
In the first Green Camp in 1996, Tang took a group of college students to ethnic Tibetan areas of Yunnan Province where timber companies had clear-cut many mountainsides. In December, 1995 the students came together in a "Save the Snub-nosed monkey" campaign and planned their first joint environmental action. The student environmental protection organizations, which by the Spring of 1996 had several hundred members each, prepared for a summer 1996 'Long March' to save the Snub-nosed Monkey through environmental education, and fund-raising campaigns on campus. The efforts of the students were reporting sympathetically by Chinese press and television. From July 25 to August 25, twenty-two college students, master's degree students and PhD candidates from Beijing, Kunming, Yunnan, and Harbin along with ten media people traveled in the Baima Xueshan area under the leadership of Tang Xiyang. The group aimed to learn how to protect the Snub-nosed monkey by studying the ecology, economics and society of the very poor Tibetan minority region on near China's international boundary with Burma and Yunnan Province's internal border with the Tibetan Autonomous Region.
After their trek through the forests of Deqin County, the students had meetings with county officials and then with Yunnan Province officials in Kunming. When they presented their report to government officials, including representatives of the Ministry of Forestry and environmental officials, the students were attacked by Forestry officials and praised by the environmental officials. The student trip got extensive coverage in the official Chinese media. Ten press and television journalists accompanied the students. Chinese media reports pointed to the slash-and-burn agriculture of the local people as the cause of the devastation of the Snub-nosed monkey habitat, but did not mention the much more important role of the Deqin County timber company. Although the threat to the Snub-nosed monkeys of Deqin County has passed, the students fear that unrestrained clear-cutting in nearby areas will continue to cause severe environmental damage. From 1996 he has been organizing "Green Camps", which in turn has led to spin-off camps in many parts of China. The last years he has been a tireless lecturer, in 2005 alone he delivered 130 lectures in 17 cities.
A Green World Tour  was published in English translation in 1999.
Tang believes that Chinese shortcomings in the areas of human rights and democracy are among the most important causes not only of human tragedy but also environmental devastation. "A Green World Tour" does not touch often on political topics, but these portions were heavily censored. Several Tang's views on Chinese politics and society are excerpted below. 
- “In my society, the word “people” is both infinitely great and infinitely small. It is great because it is an inseparable part of such weighty terms as “people’s republic,” “people’s congress,” “the dictatorship of the people,” and “Long live the people!”. It is small because people are so insignificant. One day a person may be a State Chairman; the next day a jail inmate; on day a famous general, the next day a victim in a dunce cap being paraded through the streets; one day a famous writer, the next day a body drowned in a lake; one day a world champion, the next day a figure hanging from a tree. There are well-known cases out of hundreds of thousands of frame-ups that caused loss of life, family separations, the denunciations of fathers by sons. Most people have had their names cleared by so-called rehabilitation, but what does that mean to people who are already dead? And what about those whose cases have been mishandled and not yet redressed, for whatever reason? This is a human tragedy. Yet the chief perpetrators of these political crimes feel no regret, utter no word of apology. Instead they expect their victims to be deeply grateful and hail them as heroes. Isn’t this the typical mentality of a despotic monarch? Yet they call themselves communists. The victims in this power game as not just I or the other hundreds of thousands of wronged persons, but the destiny of our country, for which countless martyrs died, and the sincere, revolutionary aspirations of the early Mao Zedong.
- As you have noticed, a disregard for nature is widespread in China. Two types of people notice this: Chinese who go abroad and then return and foreigners who come to China. Why is there such disregard? Apart from pressures of a large population, there are many reasons which relate to political, economic and cultural factors. You raised a very important questions when you said :" I do not believe that there is such a thing as an entire people whose cultural tradition sanctions destruction of the natural environment." You question left me sleepless for several nights. I continue to ponder the question. Is the Chinese cultural tradition entirely without any nature-loving element? I have not enough learning to answer this question, so I am just expressing my feeling instead of my knowledge. Observing the present is helpful in better understanding history, and reviewing history is helpful in better understanding the present.
- The Tiananmen Square incident has left a very deep impression on me. All the newspapers, journals, radio and TV programs changed to uniform words and tone almost overnight, as if the happening involving a million people that had taken place the night before was unreal. A downright lie became 100 percent truth. In an instant intelligent men devoting themselves to the cause of democracy became criminals, while those engaged in repressing the masses were honored as "Defenders of the Republic" Beijing University, with its long history and international fame, was allowed to enroll only eight hundred new students this year, and all of them must leave Beijing to receive one year of military training. The bitter and suffocating yesterday that parted us not long ago has returned suddenly. Some people said, "This is because of the intimidation of guns." I said, "It's not entirely the power of guns but more the pernicious influence of thousands of years of traditional culture." This can be seen from the articles published following the incident, for these took a 180 degree turn—but how plausible and emotional they sounded! If you think these writings were the outcome of political and military pressure, then why did a certain Professor Chen, living in the United States, also speak against his own conscience? (His essay was published by the overseas edition of Liaowang magazine.)
Additional material censored from "A Green World Tour" are at this reference.
- The 2007 Ramon Magsaysay Award for Peace and International Understanding (Retrieved on November 29, 2007)
- Brodsgard, Kjell Eric and Susan Johnson, State Capacity in East Asia, published by Oxford University Press, p. 182
- Political Testament of Zheng Zhaonan, written to Beijing City Committee five days before she died.
- Comrade Tang Xiyang's Statement at the Beijing Middle School Meeting to Expose and Criticize the Liu Shaoqi-Deng Xiaoping Capitalist Class Reactionary Line", delivered in January or February 1967, published in the "Internal Reference" No. 2 edited by Beijing Politics and Law Academy Politics and Law Commune Red Flag Fighting Troops
- INTERVIEW_IN TOUCH WITH MR. TANG XIYANG, Autumn 2005 interview on the Friends of Nature website
- "On the Life and Death of the Martyr Zheng Zhaonan" Middle School Revolution News, No. 4, February 21, 1967
- "A Green World Tour" Censored Part II
- INTERVIEW_IN TOUCH WITH MR. TANG XIYANG on the Friends of Nature website
- "Saving the Snub-nosed Monkey: Environmental Action in China" a November 1996 report from U.S. Embassy Beijing
- "Saving the Snub-nosed monkey: Environmental Action in China" a November 1996 report from U.S. Embassy Beijing
- "A Green World Tour is Published in English"
- A Section Censored from Environmental Book "A Green World Tour"
- "A Green World Tour Censored Part II"