Abstract: The effects of selenium enrichment on the mycelia dry weight and intracellular enzyme activity of Cordycepsmilitaris were investigated and the correlation analysis was carried out by adding different concentrations of Na₂SeO₃ liquid to the culture medium.The results showed that when the selenium content was 3 mg/kg, the dry weight of mycelium was 1.51 g/100 m L, which was 19.84% higher than that of the control.When the selenium content was 7 mg/kg, the dry weight of mycelium was4.76% lower than that of the control.Excessive selenium addition inhibits the growth of Cordycepsmilitaris.The suitable amount of selenium additions could increase the activity of intracellular enzymes in different extent, but the promoting effect was different.At the p < 0.01 level, the dry weight of mycelia was positively correlated with the protease activity, R2= 0.980, indicating that protease was the key enzyme in the growth of Se-enriched Cordycepsmilitaris.When the selenium content was3 mg/kg, the mycelium dry weight and protease activity reached the maximum value, which could provide the theoretical basis for liquid fermentation of selenium-enriched Cordycepsmilitaris.