Recovery effect of ultraviolet light on the cell menbrane damage of rat erythrocytes in vitro was studied.Blood samples taken from the rat was centrifuged to separate blood cells from the plasma. The cells were washed twice with isotonic saline, resuspended in normal saline and irradiated. The cell suspensions were exposed to ultraviolet light 5 min 10-20min after γ—irradiation with 60Co γ—ray then kept at 5 ℃ for 20 hours and centrifuged. The hemoglobin of the supernatants was determined. The main results obtained may be summarized as follows:Ultraviolet light decreases radiation-induced hemolysis. The cell suspension of rat erythrocytes exposed to ultraviolet light 5 min 10-20 after irradiation with 300Gy, the radiation-induced hemolysis decreased twice more than that of the control. Hewever, the differences between control and ultraviolet light treated ones are statistically significant （P＜0.05).