Objective:To develop a HPLC for determining the contents of four anthraquinones in Yiqing granules by a single marker(QAMS).Method:RP-HPLC was performed on an Accurasil C 18 column(4.6 mm × 250 mm,5 μm),eluted with a mobile phase of methanol-0.4% phosphoric acid solution(85∶ 15).The flow rate was 1.0 mL·min-1.The column temperature was set at 30 ℃ and the detection wavelength was 254 nm.Using emodin as an internal reference substance,the contents of four anthraquinones in 11 batches of Yiqing granules was authentically determined by QAMS,and compared with the measured values by external standard method.Result:Recoveries of rhein,emodin,chrysophanol and physcion were 103.6%,98.8%,99.5%,99.4% with RSD were 0.29%,1.8%,2.7%,3.8%,respectively.f rhein/emodin = 1.14,f chrysophanol/emodin = 1.47,f physcion/emodin = 1.04,r rhein/emodin = 0.64,r chrysophanol/emodin = 1.38,r physcion/emodin = 1.88,there were no significant differences between results determined by the two standard method.Conclusion:This method was simple and reliable,it could be used for determination of the four anthraquinones inYiqing granules.