Objective：To improve the pretreatment method described in ChP （2005 Edition, Vol I ） for the determination of sarsasapogenin in Rhizoma Anemarrhenae. Methods： According to orthogonal design L9 （33）, the extraction time, alcohol concentration, extraction frequency,etc, were modified to achieve the best extraction outcome with ultrasonic wave extraction. Results： The optimal extraction condition included 70%0 alcohol and twice ultrasonic wave extraction,20 min each time. Finally hydrolization was applied to obtain sarsasapogenin for determination. Conclusion： Compared with the pretreatment method in ChP, this improved extraction method shows a higher sarsasapogenin content in determination and is more accurate in reflecting the true content of sarsasapogenin in Rhizoma Anemarrhene