Abstract: Objective To observe the protective effect and action mechanism of Sisheng Decoction on ⁶⁰Co radiation-induced injury of mice. Methods Kun-Ming mice were divided into control,model,and low,medium,high Sisheng Decoction dosage groups after ⁶⁰Co irradiation.Spleen and thymus indexes and all kinds of blood cells were counted.Oxidative stress was estimated using SOD,MDA and TAOC in mice following ⁶⁰Co irradiation.Micro-nucleated cells of bone marrow were calculated. Results Sisheng Decoction increased the spleen and thymus indexes and serum SOD and TAOC activities,while decreased the MDA production in mice ⁶⁰Co irradiation compared to model group in a dose-dependent manner,showing that Sisheng Decoction can increase the number of whole blood cells and micro-nucleated bone marrow cells in mice after ⁶⁰Co irradiation. Conclusion Sisheng Decoction can protect bone marrow hematopoietic function of mice,reduce toxicity of ⁶⁰Co irradiation to peripheral blood,and inhibit ⁶⁰Co irradiation-induced oxidative damage in mice.