Inhibition action of tea saponin,capcaicin and their mixture against Fusarium oxysporum was assayed in the laboratory using growth velocity method.Bioassay results showed that there were synergistic inhibition to growth of Fusarium oxysporum,LC50= 0.06344,CTC=122.73.Using the two compounds and the mixture could inhibit the growth of hypha but not killed it.When the mycelial suspension was treated with benalaxyl（1mL）,the results showed that the hyphae grew shorter with a few of branches.Mycelia septums emerged earlier,and ageing quickly,cell wall was thinner.