Abstract: OBJECTIVE To determine the contents of rhynchophylline and isorhynchophylline from different parts of Uncaria rhynchophylla by HPLC and compare the difference of contents. METHODS Rhynchophylline and isorhynchophylline were used as reference substances. CAPCELL PAK C₁₈(4.6 mm×250 mm, 5 µm) was used for chromatographic separation. The mobile phase was acetonitrile-0.1% triethylamine solution(adjust pH to 9 with 1% phosphoric acid). The flow rate was 1 mL·min^-1, the detection wavelength was 245 nm, the column temperature was 30℃ and the injection volume was 10 µL. RESULTS Rhynchophylline and isorhynchophylline separated well. The linearity, repeatability and recovery also met with the requirements. There were difference from different parts in U. rhynchophylla. This study showed that the contents of rhynchopylline and isorhynchophylline were in an order as:bark > stem > hooked stem > leave. Rhynchophylline and isorhynchophylline could not be detected in stem parenchyma and xylem. CONCLUSION The results of this study provide a basis for the full utilization of U. rhynchophylla.