The paper reports on the changes of combined chromosome aberrations induced γ-rays irradiation and benzene in human blood lymphocytes. The results were summarized as follows: The chromosome and chromatid type aberrations can be induced by benzene. Neither dicentics nor rings were observed. When the cells were treaded with benzene, the yieald of chromosome aberration induced by radiation can be enhanced. In the definite dose range, the chromosome aberrations induced by radiation combined with benzene were increased as benzene concentation increasing for gave radiation dose. Benzene concentration and total aberration cells give a good fit to the linear regression equation. There were good relations between doses of radiation combined with tree variant benzene concentration and chromosome aberration rate. All of them give a good fit to the power regression equation.