Abstract: Fermentation of strain A11 showed antagonism pathogenic fungus such as Exserohilum Helminthosporium turcicum, Colletotrichum gloeosporioide, and so on. Antifungal substances in fermentation of strain A11 can keep activity at neutral, alkaline. But antifungal substances begin to lose activity at extreme neutral and extreme alkaline. It can preserve it’s inhibitory to pathogenic fungi when autoclaved at 75℃ for 60min, However, this substance was not stable ,it loses activity when temperature up to 100℃.