Abstract: Strain 97of Actinomycetes with high activity to P. parasitica var. nicotianae was isolated from the tobacco field soil sampls collected in Linyi and Rizhao areas of Shandong province. A study on antifungal action and stability of bioactive metabolite produced by Actinomycete strain 97 fermentation was launched by means of growth speed method for the sake of evaluating the antifungal action and physicochemical characteristics of inhibitive factors of strain 97.The results showed that the bioactive metabolite had a broad antifungal spectrum and exhibited antagonistic abilities to several plant pathogens.In addition,it still had a high activity when stored up at 4℃,and was stable to acidic,neutral and heat,maintained the antifungal activity after treatment of proteinase K and ultraviolet radiation.