Abstract: In order to study effect of Cordyceps militaris on humoral immunity and cellular immunity functions of mice.ICR male mice were assigned randomly to I,II,III groups.Every group was assigned to the following groups:negative control,low( 0.167 g / kg·bw),medium( 0.333 g / kg·bw),high( 0.999 g / kg·bw) dosage CM for 30 days by intragastric infusion. Then spleen lymphocyte proliferation,delayed type hypersensitivity,quantity of antibody forming cells,and hemolytic value( HC₅₀) were detected. The results showed that Cordyceps militaris had no significant effect on body weight increase,ratio of spleen weight to body weight,ratio of thymus weight to body weight( p > 0.05). Medium and high dose groups had significant effect on cellular immunity( p < 0.05); and had significant effect on humoral immunity,all groups had significant effect on quantity of antibody forming cells,and medium and high dose groups had significant effects on HC₅₀( p < 0.05). So it was concluded that Cordyceps militaris can strengthen immunity functions of mice,and lay the foundation for mechanism research of immune regulation.