The effects of asarum essential oil on hypha growth and spore germination of five pathogens (Botrytis cineroa, Cercospora citrullina,Corynespora cassiicola,Fuarium axysporum,Fusarium solani)in cucumber were studied in this paper.The growth rate method and spores germination method were used to determine the activities.The results showed that the asarum essential oils hads significant antibacterial activity on tested pathogens,while effects on hypha growth of Cercospora citruUina,Corynespora cassiicola and Fuarium axysporum were higher than that on spores germination,and on spores germination of Botrytis cinerea and Fusarium solani were higher than that on hypha growth.The effect on hypha growth and spores germination of Botrytis cinerea was the best,EC_(50)160 mg/L and EC_(90)350 mg/L.The effect on hypha growth and spores germination of Botrytis cinerea was the worst,EC_(50)700 mg/L and EC_(90)2 000 mg/L.