Abstract: To evaluate the compatibility of common pesticides with Isaria fumosorosea, the impacts of thirteen common pesticides on spore germination, mycelia growth and sporulation of I. fumosorosea were tested. Results showed that the tested insecticides with I. fumosorosea were more compatible than the tested germicides. The compatibility of beta cypermethrin with the fungus was the best, it had the lowest inhibition rate on the spore germination and mycelia growth (2.42% and 1.62%), and had no inhibition on sporulation of the fungus at the conventional concentration. Bacillus thuringiensis and cypermethrin showed moderate compatible with the fungus, which inhibition rates on conidial germination, mycelia growth and sporulation were 6.05%, 2.83%, 22.41% and 16.3%, 7.81%, 16.67%, respectively. Cyhalothrin, chlorfluazuron and profenofos showed lower compatibility with the fungus. However, propiconazole, chlorothalonil, tebuconazole, trichodermaspp, emamectin, avermectins and benzoate were hardly compatible with the fungu.