Abstract:［Objective］ To isolate and screen antagonistic actinomyces strains with inhibitory activity on Setosphaeria turcica from soil． ［Method］Actinomycetes were isolated by Pour Plate method． Antagonistic actinomycetes were screened by confrontation culture，cylinder plate，suppression of mycelial growth and spore germination method in vitro． Strain BZ45 were identified by morphological，cultural，physiological and biochemical characteristics and 16S rDNA sequence analysis． The fermentation condition was optimized by single factor and orthogonal experiment． ［Result］ Strain BZ45 showed antagonistic to 8 plant pathogens． Its filtrate inhibited the mycelial growth and spore germination of Setosphaeria turcica CC9．Strain BZ45 belonged to Streptomyces spectabilis． The optimum culture conditions of strain BZ45 were with a medium of 1.5% fructose，3.0% peptone，0.1% KH2 PO4，0.04% NaCl，0.1% CaCO3 at initial pH of 7.2，liquid volume 50 mL in 250 mL flask，200 rpm at 28℃，inoculation size of 10% for 4 d． ［Conclusion］ Strain BZ45 was identified as Streptomyces spectabilis and antagonistic against Setosphaeria turcica CC9．