Abstract: Ultrasonic-assisted solvent extraction of oleanolic acid and ursolic acid from Micromeria biflora Benth., was studied and compared with solvent reflux extraction. The solvent was selected based on single factor experiments and the extracting process was optimized by orthogonal test. Using ethanol as solvent, the best results can be achieved under the following conditions:90% (volume fraction)ethanol, solid-liquid ratio 1:15, ultrasonic power 360W at 40kHz, extracting for 2 times, each time 20min, total yield of oleanolic acid and ursolic acid was 0.732%; for solvent reflux extraction the optimal parameters were:solid-liquid ratio 1:15, extracting 2 times at 90℃, each time 30min, total yiled of oleanolic acid and ursolic acid was 0.706%. Ultrasonic-assisted solvent extraction can effectively extract oleanolic acid and ursolic acid from M. biflora with advantages of simple operation andhigh efficency.