The present invention relates to a process of acid hydrolyzing ginsenoside to prepare protopanoxadiol. By means of adding protecting agent and inert gas, controlling reaction temperature and acid concentration and other techonlogical measures, the present invention solves the problems of ginsenoside in acid hydrolyzing condition, including being unstable, easy to destroy and easy to cyclize, and completes the process of direct acid hydrolyzing to prepare protopanoxadiol. The present invention makes it possible to prepare protopanoxadiol in simple process, low cost and great amount so as to meet the requirement of providing medicinal resource for anticancer and cardiac vascular disease resisting medicines. |