The astronauts took off from the Jiuquan Satellite Launch Centre in northern China.
They will dock with the experimental Tiangong 2 space lab and spend 30 days there, the longest stay in space by Chinese astronauts.
This and previous launches are seen as pointers to possible crewed missions to the Moon or Mars.
The spacecraft, Shenzhou-11, took off from at 07:30 local time on Monday (23:30 GMT), lifted by a Long March-2F rocket.
The astronauts will spend the next month conducting experiments on the Tiangong 2.
The Chinese large modular space station is a planned space station to be placed in Low Earth orbit. The planned launching date of the Mir like Core module is around 2018 according to CCTV news reports in 2016. In 2017 the Chinese will launch the Tianzhou-1 cargo craft, based on the Tiangong 1 and 2 space labs.