Objective: To establish a method of high performance liquid chromatography (HPLC) for the determination of morphine in Xiaoyanzhike Tablets. Method: The method of high performance liquid chromatography was carried out on a column of Sinochrom-C18 using the mobile phase of acetonitrile-0.1 mol·L-1 potassium dihydrogen phosphate solution-methanoic acid (7.5:92.5:0.1) with a flow rate of 0.7 mL·min-1. The detection wavelength was set at 284 nm. Result: The calibration curve of morphine was linear over the range of 42.40-424.0 mg·L-1(r=0.999 9). The average recovery was 100.25% (RSD 1.67%). Conclusion: The method is simple and feasible

which can be used to determine the content of morphine in Xiaoyanzhike Tablets.