Abstract:In order to define the potential application of strain 10-4 to plant diseases in biological control, using agar block method, inhibition rate of mycelium growth and bonsai experiment in greenhouse to determine the bactriostasis, the classification status of 10-4 was confirmed by multiphase taxonomy. The results showed that strain 10-4 had strong inhibiting activity to all 20 plant pathogenic fungi, especially to Bipolaris sorokiniana, Magnaporthe grisea, Alternaria solani, Rhizoctonia solani, Geaumannomyces graminis, Colletotrichum gloeosporioides and Exserohilum turcicum,the inhibition rate of mycelium growth were exceed 90%. The metabolite of strain 10-4 showed teratogenic effects on mycelia of plant pathogenic fungi. The original fermentation and its five times dilution of strain 10-4 showed strong biocontrol effects on tomato early blight with 77.2% and 70.9% respectively.According to the morphology,cultural, physiological and biochemical characteristics, chemical components of cell wall and 16S rDNA sequence, the strain 10-4 was identified as Streptomyces saprophyticus.