Under the command of the ground-based monitoring network, the power-generating, placing, measuring, data management systems and various scientific instruments loaded into the module were all operating normally, the agency said.
All the animals returned to Earth alive when the Shenzhou return capsule touched down in the inner Mongolian region on Tuesday, the source said.
Chinese state media had said only that "various life forms'' including animals, plants, aquatic creatures, microbes and cells made the journey into space, but gave no details.
The Shenzhou II mission was the second test flight for the technology that China hopes will take the country's first astronauts into orbit and make it a major space player.
Return tests
The official Chinese news agency Xinhua said that part of Shenzhou II, its orbital module, continued to function normally. It is expected to remain in space for at least six months.
Under the command of the ground-based monitoring network, the power-generating, placing, measuring, data management systems and various scientific instruments loaded into the module were all operating normally, the agency said.
Experts quoted by Xinhua said the continued operation of the orbital module was an important technological measure, which would benefit the spaceflight programme.
Shenzhou II consisted of three sections: a forward orbital section, a return capsule and a rear propulsion module.
The capsule and its contents have been transported to Beijing for tests.
Intensive training
Last month, state media said China aimed to put an astronaut into space within five years, setting an official timetable for the first time.
In 1999, China announced a four-step manned spaceflight plan, with the aim of establishing a space station served by shuttle-style vehicles.
"The successful launching and recovery of Shenzhou II indicates China's manned spaceflight technology is advancing and has laid a solid foundation for the country to eventually conduct manned space flights,'' state media said this week.
The People's Daily newspaper quoted an unnamed expert at the China Aerospace Science and Technology Corporation, who said China needed "three to four more test flights of unmanned space aircraft" before it could send a human into space.
Luan Enjie, director of the State Aerospace Bureau, also quoted in the People's Daily, said that the country's first generation of astronauts were "receiving intensive training."