Abstract: OBJECTIVE To establish a method to determine and study the content of total phenolic acid and gallic acid in Ephorbia helioscopia L. in Chongqing. METHODS The content of total phenolic acid was determined by ferric chloride-ferricyanatum Kalium colorimetric method. In this method, gallic acid was used as the reference substance and UV detection wavelength was 720 nm. The content of gallic acid in Ephorbia helioscopia L. was determined by HPLC with an Hypersil C₁₈ column(250 mm×4.6 mm, 5 μm). The chromatographic conditions included the mobile phase consisting of acetonitrile-0.1% phosphoric acid water solution(10∶90) at a flow rate of 1.0 mL·min^-1, and UV detection wavelength was 270 nm. RESULTS A good linear relationship at the range of 6.75-67.5 μg(r=0.999 5) was obtained while determining total phenolic acid and the average recovery was 97.41%. Also a good linear relationship at the range of 0.52-5.2 μg(r=0.999 8) was obtained while determining total gallic acid and the average recovery was 98.02%. The content of total phenolic acid and gallic acid in various populations were different. The content of total phenolic acid in Ephorbia helioscopia L. was 5.327-5.464 mg·g-1. The content of gallic acid in Ephorbia helioscopia L. was 0.995-1.087 mg·g_-1. CONCLUSION The mothod is suitable for quality control of Ephorbia helioscopia L.. The experiment can be reference to the quality appraisal for Ephorbia helioscopia L..