Among the many special factors in the space environment,space radiation especially high energy heavy ion radiation is widely regarded as one of the crucial factors that hazard the health and safety of astronaut.It is well known that biological effects of radiation are dependent on the linear-energy-transfer(LET)of the emergent beam.Heavy ions have high LET and could induce complex and clustered DNA damage,which is more difficult to be repaired than individual lesions and is even irreparable.