OBJECTIVE:To establish an HPLC method for the determination of the concentration of tetrahydropalmatine in Puyuan weikang capsule. METHODS: The HPLC separation was performed on Venusil XBP-C18 chromatographic column (150 mm?6.0 mm, 5 ?m) with mobile phase consisted of methanol-0.1% phosphoric acid solution(60∶40, with pH adjusted to 6.0 using triethylamine) with a flow rate of 1 mL?min-1. The detective wavelength was set at 280 nm and the column temperature was set at 25 ℃. RESULTS: The linear range of tetrahydropalmatine was 2.5～100 ?g?mL-1 (r=0.999 6) and the recovery rate was 94.33%(RSD=1.11%,n=6). CONCLUSION: The method developed in the study was proved to be simple, rapid and accurate, and applicable for the quality control of Puyuan weikang capsule.