Water soluble ginkgo albumin extract (GAE), which was extracted for the first time from seeds of ,Ginkgo bilbo L, in our laboratory. has good antioxidant and anti-aging activity. In this paper, protective effect of GAE on γ−rays irradiated mice was studied. The results showed that the mice irradiated to 8.5Gy was zero, whereas survival rate of the high dosage GAE group was 20 percent. Blood picture of the 8.5Gy irradiated mice suffered damages of different degrees, while blood picture index of the GAE group decreased slower and recovered faster significantly than the irradiation control group. GAE and Vitamin C could significantly enhance serum SOD activity in serum and increase DNA content in bone marrow cells, and also promote recovery of damaged immunology function of the irradiated mice. These suggest that GAE may protect mice from the radiation damages by enhancement of antioxidant activity, hemopoiesis function and immunologic function of mices.