By Paul Rincon
Science reporter, BBC News
China has already launched two manned flights
China will launch its third manned space mission in late September, state-run news agency Xinhua reports.
The Shenzhou VII flight will feature China's first ever space walk, which will be broadcast live with cameras inside and outside the spacecraft.
Three "yuhangyuan" (astronauts) will blast off on a Long-March II-F rocket sometime between 25 and 30 September.
Previous reports in state media had put the launch in October, possibly during the National Day holiday.
In 2003, China became only the third country in the world to send a human into orbit. It followed with a two-man mission in 2005.
The spacecraft will be launched from Jiuquan Satellite Launch Centre in the country's north-western Gansu province.
Technicians have been busily checking the readiness of the spacecraft, which will carry the crew into orbit on a mission lasting up to five days.
This flight will be more technically demanding than the last.
For the spacewalk, two crew members will go into the spacecraft's vacuum module. One yuhangyuan will carry out the spacewalk; the other is there to monitor the activity and assist in case of an emergency.
China highlighted its space successes during the Beijing Olympics
Two types of spacesuits - one made in China, the other from Russia - will be carried up on the flight.
It is unclear why China has opted for two different types of spacesuit.
Spaceflight analyst Dr Morris Jones commented that China might want to test the suits against each other. Alternatively, he said, it might not be ready or willing to fly a mission exclusively with its own suits.
The crew members, whose identities have not been released, have been training in a water tank to get used to weightlessness and to study procedures for the flight.
The Shenzhou spacecraft closely resembles the Russian Soyuz capsules, but is substantially larger. Unlike the Soyuz, it has an orbital module that is equipped with its own propulsion, allowing autonomous flight.
Testing of the spacecraft and the Long-March II-F rocket which will loft it into orbit is now complete, a Chinese space official told Xinhua.
Engineers have reportedly made over 30 technical improvements to the new rocket.
"There were some rocket vibrations after it took off which sometimes made our astronauts experience physical discomfort," Jin Muchun, the Long-March II-F's chief designer, told the state-owned television channel CCTV9 in July.
"So we have been trying to eliminate the vibrations by changing the frequency of the engine and the electric circuit of the rocket."
According to reports, a small satellite will also be launched during the mission.
China launched an unmanned Moon probe last year about one month after rival Japan blasted its own lunar orbiter into space.
In July, Dr Michael Griffin, the head of the US space agency (Nasa), told BBC News that China was capable of sending a manned mission to the Moon in the next decade, if it so wished.