Abstract: The root of Leptopus Chinensis was extracted with petroleum ether, chloroform and methyl alcohol by Sohxlet method. Insecticidal activities of crude extracts and fractions against Plutella xylostella larvae were tested. The results showed that the different extracts from the root of Leptopus chinensis had strong Antifeeding effect and a certain Growth and development inhibited effect, but the Contact toxicity and the Stomach toxicity were very weak, The methyl alcohol extract had a certain oviposition deterrence activity against Plutella xylostella adults, but the other two extracts didn't have. Of the three extracts, the chloroform extract was indicated that possessed the strongest bioactivities.