Six strains of antagonistic actinomycetes against Phytophthora capsici were isolated and screened from soil samples of pepper planting areas in Changsha, Hengyang and Yueyang, Hunan Province. The results showed that the 5 times sterile dilution of the fermentation broth of strain L57-60 had 98.61% inhibition effect on Phytophthora capsici. Strain L57-60 was identified as Streptomyces olivaceus by morphological characteristics, physiological and biochemical identification, combined with joint tree established based on 16S rDNA, recA, atpD and rpoB genes. Antimicrobial spectrometry showed that fermentation broth of strain L57-60 showed antagonistic effect on 12 pathogens including Fusarium oxysporum in pepper, Colletotrichum micotianae in tobacco and Thanatephorus cucumeris (Frank) Donk. The fermentation medium of strain L57-60 was optimized by orthogonal experiment. The results showed that the optimal fermentation medium formula for strain L57-60 was composed of corn flour 4%, soybean flour 0.5%. Pot experiment showed the control effect of strain L57-60 against Phytophthora capsici was 73.1%.