Abstract: Using Neoseiulus cucumeris carry Paecilomyces fumosoroseus is a new idea of biological control of aphids and spider mites in eggplant, in order to verify its feasibility, the germination condition and toxicity of P. fumosoroseus were studied. The optimum germination temperature and humidity were tested by the method of small container air humidity control, and the toxicity to aphids and spider mites with 1×10⁴-1×10⁸ spore/mL was also tested under optimum conditions. The pot experiment had 6 treatments: (1) CK; (2) released 50 N. cucumeris; (3) sprayed 20 mL spore suspension liquid of 10⁷ spore/mL; (4) sprayed 20 mL spore suspension liquid of 10⁷ spore/mL then released 50 N. cucumeris; (5) released 20 N. cucumeris with conidia powder; (6) released 50 N. cucumeris with conidia powder. The results showed that the optimum germination condition of P. fumosoroseus conidia was 25-30℃ and RH 95%-100%, the accumulated revised mortality of aphids and predatory mites was 86.52% and 41.78%, respectively, under this condition and spore suspension liquid of 10⁸ spore/mL in ten days, the toxicity on aphids was far more than that on predatory mites, which met the condition of a kind of carrier to prevent aphids. From the pot experiment, the number of aphids of treatment (3), (4) and (6) was close to 0 at the 8th day, and the method could also save labor and time. The study proved that using Neoseiulus cucumeiris carry Paecilomyces fumosoroseus to prevent aphids and spider mites in eggplant was a feasible method.