Abstract:The fermentation medium and conditions of ’Actinomycetes 769’ against Magnaporthe grisea were stu died.The results indicated that the most appropriate fermentation medium was medium F.Furthermore,the carbon source,nitrogen source and mineral salts were optimized by Orthogonal experiment.The results showed that the optimum combination of medium and the optimal component were 2.0% soybean powder,1.5% corn powder,1.0% sucrose,0.60% beef extract,0.3% CaCO3,0.5%(NH4)2SO4,0.3% NaCl,0.1% MgSO4,0.02% KH2PO4 and 0.01% FeSO4,respectively.In this research,the optimum fermentation condition to enhance antibiotic activities of ‘Actinomycetes 769’ were as follows: culture temperature 28℃,pH 6.72,and seed age 28 hours,inoculation volume 4%,70 ml liquid medium in 250 ml flake,180 romin-1,and 72 hours in shaker.