This paper reported dynamic changes of micronuclei and cell survival in human liver cancer cells SMMC-7721 irradiated by 25MeV/u,40,Ar,14+,. The results show: (1) Change rules of frequency of micronuclei induced by single irradiation and fractionation irradiation with culture time have not clear difference. (2) Irradiated (single, fractionation) liver cancer cells grow much slower than control and their survival number with culture time shows decay tendency. (3) Dynamic changes of the relationship between micronucleus frequency and cell survival number presents negative correlation. (4) For cells irraddiated by dose of 0.68Gy, 6.8Gy and 68Gy,frequency of micronuclei following culture 24 hours is lower than that following culture 96 hours. (5) Negative dependences of survival number of liver cancer cells for culture 24 hours and 48 hours on dose are demenstrated.