[Objective] To extract and determine the content of emodin in Polygonum perfoliatum L.[Method] The content of emodin was determined by reverse phase HPLC.A column of Kromasil C18 was used and a mixture of methanol-water-glacial acetic acid(87∶13∶215) was used as the mobile phase at a flow rate of 110 ml/min.The UV detection wavelength was 254 nm and the column temperature was room temperature.[Result] The emodin showed a good linear relationship within the range of 1-40 μg/ml(r=0.999 9) ;the linear regression equation was Y=112.89X-8.912(r=0.999 9) .The optimum extraction technology was 80% ethanol concentration,35 ml ethanol dosage and 2 h extraction time.The average recovery rate was 99.16%(RSD=1.49%) .[Conclusion] The method was simple,rapid and accurate.It could be used for the extraction and content determination of emodin from Polygonum perfoliatum L. [Objective] To extract and determine the content of emodin in Polygonum perfoliatum L. [Method] The content of emodin was determined by reverse phase HPLC. A column of Kromasil C18 was used and a mixture of methanol-water-glacial acetic acid (87 : 13: 215) was used as the mobile phase at a flow rate of 110 ml / min. The UV detection wavelength was 254 nm and the column temperature was room temperature. [Result] The emodin showed a good linear relationship within the range of The linear regression equation was Y = 112.89X-8.912 (r = 0.999 9). The optimum extraction technology was 80% ethanol concentration, 35 ml ethanol dosage and 2 h extraction time The average recovery rate was 99.16% (RSD = 1.49%). The method was simple, rapid and accurate. It could be used for the extraction and content determination of emodin from Polygonum perfoliatum L. [