Abstract: This paper described of enzyme-linked immuno-sorbent assay in detecting the poplar mosaic virus.Enzyme was used horseradish peroxidase.Enzyme conjugate was prepaped by pentamethylene aldehyde double method,ELISA was carried out in anti-PMV IgG coated polystyrenemicrotitre plates,purified PMV was used to immunize rabbits for the preparation of antiserum,from which anti-PMV Igc was purified by ammonium sulfate precipitation and then DEAE-cellulose(DE-32) chromatography.In this experiment,the optimun concentration for IgG coating is 5ug/ml and optimum concentration of enzymes conjugate is 4ug/ml.The results indicated that the sensitivity of ELISA to detect purified PMV is 25ng/ml and 1:2430 dilution of diseased leaf sap.