The entire line runs underground. The excavation of tunnels using the cut-and-cover method resulted in large scale detouring of road traffic. Because of that, the line runs beneath existing roads and totals 28.3 km (17.6 mi).
Due to Taipei City Hall being at the centre of the Taipei 101 New Year's festivities, intervals between trains can be reduced to a minimum of 135 seconds, transporting up to 39,000 passengers per hour. This results in an average of about 27 trains per hour on the line during peak hours.
27 May 2006: The segment from Banqiao to Tucheng opens for trial operations.
31 May 2006: The segment from Xinpu to Yongning begins revenue service.
16 May 2008: The Nangang section eastern extension to Nangang begins trial service.
25 December 2008: The Nangang section eastern extension to Nangang begins revenue service.
February 27, 2011: The rest of the Nangang section eastern extension to Taipei Nangang Exhibition Center opened for service.
21 May 2014: The 2014 Taipei Metro attack occurs between Longshan Temple and Jiangzicui when 21-year-old university student Cheng Chieh attacked passengers with a fruit knife, leading to 4 deaths and 24 injuries.