Urban rail transit in China encompasses a broad range of urban and suburban electric passenger rail mass transit systems including subway, light rail, tram and maglev.^[1] Some classifications also include non-rail bus rapid transport. As of 31 December 2023, China has the world's longest urban rail transit system with more than 10,000 km (6,200 mi) of urban rail nationwide in 49 systems in 47 cities, accounting for 9 of the 10 longest metro systems, with the exceptions of the Moscow Metro^[2] or metro systems in Seoul combined if metro systems in the same cities are merged in the rank.

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China has put 233 urban rail transit lines into operation in 44 cities with length more than 7,500 km (4,700 mi) by 2020,^[3] and 6,100 km (3,800 mi) by 2019.^[4] Half of the top 10 busiest metro systems are in China,^[5] and the Beijing Subway, though started operating in 1971, is now the longest metro system worldwide.^[6][7][8]

Several Chinese cities had urban electric tramways in the early 20th century, most of which were dismantled in the 1950s–1970s. The only surviving tramways are in Dalian (Dairen) and Changchun (see trams in Dalian and trams in Changchun). Nanjing (Nanking) had an urban railway [zh] from 1907 to 1958.

The first subway in China was built in Beijing in 1969 (but it was only handed to civilian control in 1981 and trial operations ended later in the same year; before which credentials were required). The Tianjin Metro followed in 1984. The MTR Corporation Limited from across the border in Hong Kong has investment, consulting and management stakes in the rapid transit systems of several mainland Chinese cities (having completed their first section of subway and entered into revenue operation in 1979 in New Kowloon, at the time when the territory was under British rule).

The rapid growth of the Chinese economy since the 1980s has created a huge surge in demand for urban transport. This prompted cities across China to pursue and draft proposals for subway networks, with Shanghai and Guangzhou opening their first sections of subway in the 1990s, inspiring more cities to propose subway networks. In 1995, the Central Government, alarmed by the high cost and financial debt from these ambitious subway plans, put out a "notice on the suspension of approval of urban underground rapid rail transit projects" barring new subway systems outside of Beijing, Tianjin, Guangzhou and Shanghai from being built.^[9] At the time Nanjing, Wuhan, Chongqing, Dalian and Shenzhen had advanced proposals waiting to be approved. Wuhan, Chongqing, Dalian managed to circumvent the moratorium on subway construction by constructing and opening lower cost elevated lines, light metros, and monorails in the early 2000s. Changchun was the first city constructing real light rail system in China, which began operation in 2002. Its first transit line, Line 3, is a light rail line not fully grade separated, still having four level crossings as of 2023. It's also the only rapid transit system combined light rail and rapid transit lines in China, which can directly transfer to each other.^{[citation needed]}

Rapid urbanization of China led to severe congestion and pollution in urban areas leading to the suspension being lifted. Initially, light metro lines using small profile and shorter rolling stock were constructed to reduce costs. It was assumed that as ridership grows the line will operate trains at a low headway to increase capacity. This design paradigm was known in China as "small rolling stock, high density" operation.^[10][11][12] However, after a few years operating, many of these lines such as Guangzhou Metro Line 3, Line 6, Shanghai Metro Line 6, and Line 8 were severely overcapacity. Guangzhou Metro Line 3 was able to reconfigure from 3-car trains into 6-car trains to slightly relieve overcapacity. This led many cities such as Beijing, Guangzhou, Wuhan and Chengdu to use higher capacity designs on newer lines.^{[citation needed]}

Since the mid-2000s, the growth of rapid transit systems in Chinese cities has rapidly accelerated, with most of the world's new subway mileage in the past decade opening in China.^{[13][6][14][15]} From 2009 to 2015, China built 87 mass transit rail lines, totaling 3,100 km (1,900 mi), in 25 cities at the cost of ¥988.6 billion.^[16] In 2016, the Chinese government lowered the minimum population criteria for a city to start planning a metro system from 3 million to 1.5 million residents.^[17] As part of its 13th Five Year Plan, the Chinese government published a transport whitepaper titled "Development of China's Transport". The plan envisions a more sustainable transport system with priority focused on high-capacity public transit particularly urban rail transit and bus rapid transit. All cities with over 3 million residents will start or continue to develop urban rail networks. Regional rail networks will be constructed internally connect and integrate urban agglomerations such as the Jingjinji, Yangtze River Delta and Pearl River Delta areas.^[18][19] In 2017, some 43 smaller third-tier cities in China have received approval to develop subway lines.^[20]