Aim Adetermination method of oleanolic acid in material and oleanolic acid troches by reversed-phase high performance liquid chromtograph was established and at the time the purity of oleanolic acid was derected by means of PhotodiodeArray Detector.MethodsThe chromatographic column,Nova-Pak C_1_8(3.9 150 mm,4 μm),ethanenitrile-water(65∶35,V/V) mobile phase with 0.8 ml·min~-~1 flow rate,the detected wavelength(210 nm),and the column temperature(25℃) were adopted.Result The calibration curve of oleanolic acid was linear under the content of 3.48~17.40 μg,the correlation coefficient was over 0.9999,the detected limlt was 0.3 mg·L~-~1(3σ).The average recovery of oleanolic acid was 99.5 %.ConclusionThe method is simple,accurate and has wider linear range.The method can be adapted to evaluate the quality of medicine that contain oleanolic acid.