[en] Objective: To investigate the influences for Maitake Polysaccharide on the Immunoregulation and anti-radiating damage. Methods: The mice were divided into control group and three experiment groups. The mice of three experiment groups were fed Maitake Polysaccharide at dose of 0.15 g/kg, 0.30 g/kg, 0.90 g/kg for 30 days. 7 indexes were observed to detect the effect of Maitake Polysaccharide on the immunoregulation. The other mice were divided into radiating control group and three experiment groups. The mice of three experiment groups were fed in the same way. Then all animals were radiated by ⁶⁰Co-γ. The number of white blood cells (WBC) was counted before radiating, on 3 and 14 day after radiating. The DNA content of bone marrow cells were measured on 3 days after radiating. The activities of superoxide dismutase (SOD) in serum were measured on 7 days after radiating. Results: Maitake Polysaccharide could increase the amount of hemolytic antibody in serum. The proliferation of ConA-induced mitogenic response for spleen lymphocyte was also increased. Maitake Polysaccharide could enhance the activity of NK cell and the ability of phagocytosis significantly. Compared with the radiating control group, the number of WBC and the DNA content of bone marrow cells, and the activities of SOD in serum increased significantly. Conclusion: Maitake Polysaccharide can improve cell-mediated and humoral immune function and non-specific immune function, and protect the mice from radiation injuries. (authors)