Abstract: Space environments such as solar cosmic ray, galactic cosmic ray, microgravity, dust and dust storm, deep space microbe and so on, which will be encountered during the course of manned deep space exploration, are firstly introduced. Then, the threat of different deep space environments to the astronauts is discussed, and some countermeasures such as physical protection, monitoring and early warning of radiation risks, radiation protection drugs, astronaut selection, etc, is given. Finally, the further work should be done for manned deep space mission, which includes damage mechanism of space radiation on the astronaut, development of drug against space radiation and microgravity, protection of structure and material from space radiation environments, self cleaning materials and technology for space suit, research and development of materials against microbial erosion, etc, are discussed.