OBJECTIVE： To establish a method for contents determination of emodin， chrysophanol and physcion in Rumex japonicus，and compared the differences of components in medicinal materials from different producing areas. METHODS： HPLC was performed on the column of Agilent C18 with mobile phase of methanal-0.1％ phosphoric acid solution （gradient elution） at a flow rate of 1.0 ml/min， detection wavelength was 254 nm， column temperature was 35 ℃，and injection volume was 20 μl. RESULTS： The linear range was 2.04-24.48 μg/ml for emodin （r＝0.999 7）， 2.00-24.00 μg/ml for chrysophanol （r＝0.999 5） and 1.02-12.24 μg/ml for physcion （r＝0.999 8）； RSDs of precision， stability and reproducibility tests were lower than 2.0％； recoveries were 97.09％-102.65％（RSD＝1.79％，n＝9）， 97.10％-100.31％ （RSD＝0.97％，n＝9） and 95.45％-100.18％（RSD＝1.45％， n＝9）. CONCLUSIONS： The method is simple with high precision， stability and reproducibility， and can be used for the simultaneous determination of emodin， chrysophanol and physcion in R. japonicas.There are obvious differences in medicinal materials from different producing areas.