Abstract: Two compounds with strongly insecticidal and fungicidal activity, Kurarinone and Sophoraflavanone G , were isolated from Sophora flavescens Ait under the direction of bioassay, and comfirmed by UV, IR, MS and NMR. The insecticidal activity of flavonoids from Sophora flavescens Ait was first reported here. The study of structure-activity relationship indicated that the methylation of 5-hydroxy on the phenyl ring would decrease the insecticidal and fungicidal activity of flavonoids.