By means of the mycelium growth rate methods, effectiveness of five fungicides on cucumber Corynespora cassiicola（Berk curt） Wei was evaluated in door. The results showed that when using 35% difenoconazole-prochloraz, 25% prochloraz and 70% thiophanate-methyl, the suppressive effects on cucumber Corynespora cassiicola（Berk curt） Wei were significant, the value of Ec₅₀were 0.35 μg/ml, 0.39μg/ml and 0.37 μg/ml. But the value of EC₅₀ of 10% difenoconazole and azoxystrobin were obviously higher than that of 35% difenoconazole-prochloraz, 25% prochloraz and 70%Thiophanate-methyl. The highest value of EC₅₀（4.55μg/ml） was 10% difenoconazole, which had the worst suppressive effect.