Astronauts Fei Junlong and Nie Haisheng are in a "Shenzhou 6" space capsule, which was lifted into space atop a massive Long March rocket.
The launch at the Jiuquan space center in the Gobi Desert went well, with national television carrying the spectacle live.
Chinese Prime Minister Wen Jiabao praised the launch as a "success" and congratulated all the personnel involved.
While aloft, the two crewmen will carry out a series of experiments about which the Chinese National Space Administration has given few details.
Much more important in Chinese eyes is the journey itself, and the experience gained from carrying out what is only the country's second manned space flight.
Space scientist Andrew Coates of the Mullard space laboratory at the University College London, said that China views its growing competence in space travel as a matter of prestige.
"The manned [space] program is a purely Chinese program and is a demonstration of [their] technical capability and a great source of national pride," Coates said.
The "Shenzhou 6" capsule has two compartments, and the spacemen will be able to move between both without space suits. The second compartment, which houses living quarters and room for experiments, will be left in orbit when the return capsule is detached for the return journey.
In this way, the compartment serves as a mini-space-station, which future manned missions can visit and live in. The docking is in itself a technique China wants to master.
Wang Yonghzi, chief designer of China's manned flight program, said space walks are also planned, as is construction of a permanent space laboratory.
But all this has been done before, over the past 40 or so years. So why is China developing its own space capability now?
"So far of course, only Russia and the United States have been able to put people into space, and now China is entering that exclusive club by being able to do the same," Coates said. "In terms of its usefulness to China -- because they are obviously putting a lot of money and resources into this -- it demonstrates to the world China's technological capability."
Coates points out that the various manned space flight programs, as they have developed so far, have no military applications. That's because manned vehicles are much more expensive and cumbersome than unmanned vehicles for such a purpose.
But Beijing's plans extend further than just orbiting Earth. A separate project foresees putting a satellite in moon orbit by 2007, landing a remote control vehicle there by 2010, and taking lunar mineral samples by 2020.
No current plans are known for China to make a manned excursion to the moon, but as they develop their expertise over the coming years, that cannot be ruled out.
The United States has just announced plans for a big-scale return to lunar travel. NASA space agency said last month that it is preparing manned flight to the moon by 2018. President George W. Bush said the moon trips are a precursor to voyages to Mars and possibly other planets in our solar system. U.S. astronauts first walked on the moon in 1969.
Meanwhile, not everybody is taking space travel so seriously. American space tourist Gregory Olsen returned yesterday from a trip to the International Space Station. This was his comment on emerging from the Soyuz landing capsule:
"I feel good. I feel great. I can't wait to walk around and have some real food and take a shower."
The trip cost Olsen some $20 million -- a small price to pay, he said, for the experience of a lifetime.