The park was named after the Choi Sai Woo Reservoir, which was formerly located in the park. According to the commemorative plaque in the park, the reservoir was built by Taikoo Sugar Company Limited in 1894; it was the largest and the last of the five private reservoirs built by the company. During the drought and bubonic plague outbreak that started in 1894, the reservoir once supplied water to Tai Ping Shan District. It was filled in by Li Ka Shing to create the current park site. In World War II it was the scene of bitter fighting as the Japanese advanced to split the defence of Hong Kong into two: East and West.
Choi Sai Woo Park is a landscapedgarden with a total area of 2,400 m² providing some country freshness among a number of housing estates and schools. Located next to prestigious new housing developments and with several schools in the area, it serves the community as a place of rest. There are two small basketball courts in the Park. The garden area is located at the very bottom level of Choi Sai Woo Park abutting the car parking lot of PARKnSHOP. It is mainly planted with bamboo. There is a children's playground located at the top of the park. A pagoda adjoins the playground. A number of amenities including restaurant or tea shop "cha chaan teng", Wan King, PARKnSHOP and 7-Eleven outlets, are in the vicinity.