This paper objective was to explore biological activity of extracts from Foeniculum vulgare to Pieris rapae. Extract volatile matter was extracted from stem and leaves of Foeniculum vulgare Mill by steam distillation. Biologial activity of antifeedant effect and oviposition repellent on Pieris rapae L was tested with extraction of Foeniculum vulgare. The results showed that extracts of Foeniculum vulgare have strong antifeedant effect on Pieris rapae 3-instar larvae, which the antifeeding activities of Pieris rapae L. of non-choice was higher than that of choice tests. Moreover, that extracts of Foeniculum vulgare had strong effect of repellent effect on Pieris rapae.