Abstract: In order to further improve the cordycepin yield,Cordyceps militaris(C. militaris)CICC 14014 was considered as the starting strain for protoplast compound mutation. The protoplasts of the strain were induced by ultraviolet-diethyl sulfate(UV-DES). Then,a high cordycepin yield and stable genetic strain was obtained by screening with 96-well microplates and triangle bottles. Through primary screening with 96-well microplates,54 mutant strains with a yield greater than 6 g/L cordycepin were obtained. A strain of cordycepin high yield mutant strain UD10-2 was screened out by secondary screenings with triangle bottles. The cordycepin production obtained by C. militaris UD10-2 mutant was 11.32 g/L in liquid surface culture,which was enhanced by 108.47% more than the original strain(5.43 g/L). The results of subculture test showed that the mutant strain had stable hereditary characteristics after 20 generations.