Factors affect germination of conidium of Corynespora cassiicola were studied in the paper.The results showed that: the conidium was able to germinate after 2 hours culture with water film under the temperature of 30℃,the germination ratio reached higher level after 6 hours culture.The conidium germinated with different patterns,i.e.,some germinated from one end,some from both ends,some from one end and one side,and some from both ends and one side.Effect of dews on cucumber leaves and juice of cucumber leaves of different varieties on the ratio of germination,quantity of sprout and length of hypha was different.Juice of leaves of disease resistant cucumber varieties inhabited germination of conidium.