Abstract: Objective To study the protective effects of polysaceharides of Tremella fueiformis on hematopoietic function in radiation-injured mice.Methods Colony-forming unit of spleen(CFU-S), number of nucleated cells in bone marrow (BMNC) and spleen index were used to investigated the effect of polysaccharides from tremella fuciformis at 6mg/kg、12mg/kg、24mg/kg on hematopoietic function of mice irradiated with 7.5 Gy ¹³⁷Csγ-rays.Results On the 9 th day after irradiation compared with the negative control group number of nucleated cells in bone marrow, colony-forming unit of spleen and spleen index of mice have treated with polysaccharides from Tremella fuciformis intraperitoneally for three days prior to irradiation increased markedly.Conclusion Polysaccharides of tremella fuciformis have protective effect on hematopoietic function of radiation-injured mice.