Most injuries were light, Shanghai Shentong Metro Group company said after the incident on the line 10.
It happened after signal failure in a station, China's official Xinhua News Agency reported.
The city has expanded rapidly in recent years the u-Bahn system, and some lines have seen recurring problems.
Tuesday the incident took place close to Yu Yuan Central Shanghai to 14: 51 - about 40 minutes to Shanghai Metro failure at once.
At the time of the crash staff trains manual, Director news agency Reuters reported.
A passenger said, there was a lot of blood in the first car of the train.
Streets around the train station have been cordoned off to allow ambulances through.
A collision between two overground trains in Wenzhou, Eastern China, in July killed 40 people and provoked public outrage over safety standards.
The country's security chief said Ernst design flaws were guilt in this case.
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