Abstract: A bioassay of the crude extracts,as well as its fractions of different organic solvens partitions of A.nipponensis against four species of insect pests were carried out in the laboratory.The results showed that the methanol extract and its chloroform fraction presented a significant activity of growth and ecdysis inhibitory as well as antifecdant action against the larvae of Pieris rapae L.Plutella xylostella L,Prodexia likra and Mythimna separata Walder.As to the 5th-instar larvae of P.rapae,their antifeeding median concentrations (AFC50)of the methanal extract and its chloroform fraction were 0.31 %and 0.12%,respectively by the methed of the leaf disc tests,and their effective median dosage (ED50)of growth and ecdysis inhibition were 1.36mg/g and 0.34mg/g,respectively in quantitative feeding tests.For the 3-4th instar larvae of P.xylostella which are very resistant to the conventional insect-cides,the chloroform fraction of the crodc extract were very effective and its AFC50was 0.23% ,and its EC60 were 0.29% by feeding and C.22% by topical application.The servival adults were inhibited in oviposition.This study indicates that the main insecticidal priciples of the extracts exist in the weak pole parts.