Abstract: Unsaturated fatty acid ethyl ester product was obtained from poplar bark extract through saponification,(extraction),separation and purification,at yield 30%-36% of the extract.It consists of 95.94% esters of unsaturated fatty acid and 3.14% esters of saturated fatty acid.This product is analysed by GC.Of the 22 peaks,21 components which make up (99.19%) of the total weight were identified.The major component is linoleic acid whose content reached 94.04%.Medicine effectiveness test of the product showed that TC,TG and LDL-C in serum of high blood-(lipoid) rats(P<0.001) can be reduced obviously and content of HDL-C in serum is increased.