Objective :Rhizoma Polygoni cuspidati is a Chinese medicinal herb with large antiviral range,in order to understand and exploit it's antiviral properties,we extracted emodin of it and observed the antiherpes and anticoxsackie effects of emodin. Methods: We use ACV as positive control of antiherpes ,ribavirin as positive control of anticoxsackie,through plaque reduction assays and by way of HSV2 CPE inhibition,observe the effects of antiherpes and anticoxsackie of emodin. Results: In HEp2 cell system,the median effect dose(ED50) sofdirect virucidal activity,the inhibition effectsonthe multiplicationand infection of HSV2 333ACVare 16.45g/ml,10.85g/ml ,18.62g/ml respectively ,the corresponding figuresofemodin are 1.28g/ml ,1.40g/ml ,1.44g/ml separately.The ED50s of direct virucidal activity,the inhibition effects on the multiplication and infection of CVB3 of ribavirin are 6.26g/ml,7.55g/ml,7.50g/ml respectively,the corresponding figures of emodin are 1.54g/ml,8.34g/ml,3.06g/ml separately.HZConclusion: The treatment indices(TI) of emodin to HSV2 333 strain are 4.0,2.4,3.9 times of ACV TIs,and the TIs of emodin to CVB3 are 4.7,1.0,2.9 times of ribavirintis.It should be worth exploitation.