Objective:To investigate the effect of Superfine Cordyceps militarisv Powder on the immune functions of the mice,and to provide basis for improving the utilizable ratio of Cordyceps militaris.Methods:A total of 40 mice were randomly divided into negative control group,low dose (0.166 5 g·kg-1),middle dose (0.333 3 g·kg-1),and high dose (0.999 9 g·kg-1) of Superfine Cordyceps militaris Powder groups,and there were 10 mice in each group.The mice in different doses of Superfine Cordyceps militaris Powder groups were administered with the Superfine Cordyceps militaris Powder for 30 d by intragastric infusion respectively,whereas,the mice in negative control group were administered with the same volume of water for 30 d by intragastric infusion.The body weights,the spleen indexes and thymus indexes of the mice in various groups were measured;the lymphocyte transformation abilities of the mice in various groups were observed by lymphocyte transformation experiment;the levels of delayed-type hypersensitivity reaction of the mice were examined with toe incrassation;the number of antibody forming cells,phagocytic rate and phagocytic index of chicken erythrocytes phagocytized by peritoneal macrophages of the mice were detected.Results:Compared with negative control group,the body weights,the spleen indexes a nd thymus indexes of the mice in different doses of Superfine Cordyceps militaris Powder groups had no significant differences (P>0.05).The lymphocyte transformation abilities of the mice in middle and high doses of Superfine Cordyceps militarisPowder groups were higher than that in negative control group(P<0.05).The levels of delayed-type hypersensitivity reaction of the mice in middle and high doses of Superfine Cordyceps militaris Powder groups were higher than those in low dose of Superfine Cordyceps militaris powder group and negative control group(P<0.05).The numbers of antibody forming cells of the mice in low,middle and high doses of Superfine Cordyceps militaris Powder groups were higher than that in negative control group(P<0.05).The phagocytic rates and phagocytic indexes of chicken erythrocytes phagocytized by peritoneal macrophage of the mice in low,middle and high doses of Superfine Cordyceps militaris Powder groups were higher than that in negative control group(P<0.05).Conclusion:Superfine Cordyceps militaris Powder can strengthen the immune functions of the mice,and the recommended doses are 0.333 3 and 0.999 9 g·kg-1.