Abstract: 【Objective】Antifeedant activities of podophyllotoxin and 4′-demethylpodophyllotoxin against the adult of stried leaf beetles Phyllotreta striolata were studied. 【Method】Podophyllotoxin and 4′-demethylpodophyllotoxin were extracted and separated from Chinese umbrellaleaf rhizome. The antifeedant activities of podophyllotoxin and 4′-demethylpodophyllotoxin against P. striolata were made at 500, 1 000, 2 000, 3 000 and 4 000 μg·mL^-1 concentrations for 24 h and 48 h respectively.【Result and conclusion】Podophyllotoxin showed a selective antifeedant effect, and the activities remained unchanged as time extended. By contrast, 4′-demethylpodophyllotoxin had no obvious influence on antifeedant activities except under high concentration (4 000 μg·mL^-1). The indexes of 4′-methyl were speculated to be the key functional group to affect the antifeedant activities according to the molecular structures of podophyllotoxin and 4′-hydroxypodophyllotoxin.