Abstract: Isaria fumosorosea is one of the most important entomopathogenic fungi.Protein diversity in Isaria fumosoroseus induced by chitin at different culture conditions or not was determined by SDS-PAGE. Protein content of both the chitin-induced mycelium and the CK increased with the increase in incubation time in the potato dextrose agar (PDA) medium and the basic medium (BM), while there were obvious differences in protein content between the CK and the chitin-induced treatment at different culture time. The difference of protein content between the CK and the treatment was significant, in BM, the difference of protein content was highly significant on the 5th day. Under different temperatures, the CK and the treatment both showed the highest protein concentration at 25 ℃ and the lowest protein concentration at 31 ℃ for both PDA and BM. Protein concentration differed significantly between the CK and the treatment. SDS-PAGE showed the greatest difference in protein bands between the CK and the treatment on the 5th d and under 21 ℃ in BM. The results indicate that chitin induction at 21 ℃ for 5 days in BM is optimal.