Abstract: Objective: To observe the influence of linear alkylbenzenesulfonate(LAS) on the reproductive capacity of drosophila melanogaster,and the antagonism of isoflavone on the outcome.Methods: The reproductive capacity of the drosophila receiving different doses of LAS was detected;the antagonism of isoflavone and the interaction between isoflavone and LAS were observed using analysis of variance of factorial design.Results: The number of drosophila melanogaster of the three groups(with a dose of LAS 150 mg/kg,300 mg/kg and 600 mg/kg) was lower than that of control group(P<0.01) with a percentage of 85.07%,84.59% and 71.88%,respectively.The principal effect of soflavone had statistical significance(P=0.01),which demonstrated that isoflavone could protect drosophila melanogaster from the harm induced by LAS,but the main effect of LAS and the interaction between isoflavone and LAS were not found(P>0.05).Conclusions: LAS can degrade the reproductive capacity of drosophila melanogaster,and isoflavone can antagonize this effect.