Abstract: The ethanol extracts of walnut green husk were further extracted with petroleum ether,chloroform,ethyl acetate and n- butanol.Antifungal and antitumor activity of the walnut green husk'different solvent extracts against4 corn pathogenic fungi and 2 tumor cells were studied. The results showed that the ethanol extract from walnut green husk and different solvent extracts had certain inhibition on testing microbial.For the corn pathogenic fungi,the inhibition rate of ethanol extract to Fusarium graminearum,Curvularia lunata,Rhizotonia solani Kuhn and Ustilago maydis were 92.5%,86.0%,83.2%,50.0% respectively.The ethyl acetate extract had the best antimicrobiol activity among the different solvent extracts,which the EC₅₀ were 7.354,9.546,10.341,96.532 mg / m L. MTT assay showed that the different extracts inhibited the growth of Hela cells and Huh7.5.1 cells in a dose- dependent manner.The petroleum ether extract had the most obvious antitumor effect on testing cells,which the IC₅₀ were124.99 μg / m L and 45.33 μg / m L,it could induce Huh7.5.1 cell's apoptosis. The ethanol extracts of walnut green husk can inhibit Fusarium graminearum,Curvularia lunata,Rhizotonia solani Kuhn,Ustilago maydis and Hela cells,Huh7.5.1 cells in a dose- dependent manner.