Abstract: With the application of the immune enzyme assay,the inhibitory effects of herbal polysaccharides on the transcriptional activation of Epstein-Barr virus(EBV) early antigen in the Raji cell have been researched.The test result shows that Astragalus polysaccharide(APS),Ganoderma lucidum polysaccharide(GLP) and Epimedium polysaccharide(EPS) have inhibitory effects in certain range of dose.APS and GLP have significantly better inhibitory effects than EPS.In addition these polysaccharides and their inhibitory effects on EBV antigen expression have dose-effect relationships.In conclusion,this method can be used for finding new anti-EBV drugs in natural medicine.New anti-EBV drugs will inhibit EBV antigen expression and prevent cell carcinogenesis,so that they will be used for prevention and treatment of EBV associated disease.Furthermore the experiment reveals a new mechanism of herbal polysaccharides' anti-virus and anti-tumor effects.