Abstract: Six plant pathogens (Pyricularia grisea,Sclerotinia sclerotiorum,Phytophthora capsici,etc.) were used to screen fungicidal components from Cuminum cyminum L.seed.Cumin seeds were distilled by alcohol,and then extracted by petroleum ether,chloroform,ethyl ester,and n-butanol in sequence.Two compounds were isolated from petroleum ether extract by column chromatography.Their structures were identified as p-isopropyl benzoic acid and p-isopropyl benzaldehyde by MS and NMR.The inhibitive rate against the mycelial growth of S.sclerotiorum,P.capsici were tested.The EC50 of p-isopropyl benzaldehyde against S.sclerotiorum and P.capsici were 2.093 and 15.40 mg/L,respectively.The EC50 of p-isopropyl benzoic acid against S.sclerotiorum and P.capsici were 7.298 and 19.66 mg/L,respectively.