Abstract: Ultrasonic-assisted solvent extraction method was used to simultaneously and efficiently extract three active substances,rosmarinic,carnosic and ursolic acids from rosemary,the contents of the three substances in rosemary extract was measured by improved high performance liquid chromatography(HPLC)method. By using orthogonal test,the total yield was applied as the observatory indicator to investigate the extraction process. The optimal conditions for extraction were determined as follows:Ethanol concentration of 100%,solid-liquid ratio of 1:20 (g/mL),ultrasonic time of 30 min. Under the conditions above,the total yield of rosmarinic,carnosic and ursolic acids was up to 6.15%.