The three men – Nie Haisheng, Liu Boming and Tang Hongbo – are to spend three months aboard the Tianhe module some 380km (236 miles) above the Earth.
It will be China’s longest crewed space mission to date and the first in nearly five years.
The crew successfully docked with the space station just over seven hours after the launch.
The moment of contact was met with applause from mission control in China.
Their Shenzhou-12 capsule took off atop its Long March 2F rocket on Thursday.
Lift-off from the Jiuquan satellite launch centre in the Gobi desert was at 09:22 Beijing time (01:22 GMT).
The launch and subsequent mission are another demonstration of China’s growing confidence and capability in the space domain.
In the past six months, the country has returned rock and soil samples to Earth from the surface of the Moon, and landed a six-wheeled robot on Mars – both highly complex and challenging endeavours.
This 16.6m-long, 4.2m-wide Tianhe cylinder was launched in April.
It is the first and core component in what will eventually be a near 70-tonne orbiting outpost, comprising living quarters, science labs and even a Hubble-class telescope to view the cosmos.
It has poured significant funding into its space efforts, and in 2019 became the first country to send an un-crewed rover to the far side of the Moon.
But it’s had to go at it alone in developing a space station, in part because it has been excluded from the International Space Station project.
The US, which leads that partnership (with Russia, Europe, Canada and Japan) will not co-operate with the Asian nation in orbit.
For its part, China says it is open to foreign involvement on its station. In the first instance, this means hosted scientific experiments. For example, the Shenzhou-12 crew will conduct cancer investigations that are led from Norway. And on the outside of the station, there is an Indian-developed telescopic spectrograph to study ultraviolet emissions coming from deep space, from the likes of exploded stars.
But, long term, there probably also will be visits to the station by non-Chinese nationals.