Abstract: The present disclosure provides a preparation method of a Kaixinsan powder, including the following steps: pulverizing Radix Polygalae, Rhizoma Acori Graminei, ginseng, and Poria into a fine powder separately; and mixing each fine powder evenly in sequence according to a backing register method to obtain the Kaixinsan powder; where in the Kaixinsan powder, the fine powders each are required to pass through an 80-mesh sieve, and at least 95 wt% of each of the fine powders passes through a 100-mesh sieve. In the present disclosure, the fine powder of each medicinal material is capable of being mixed evenly, and has desirable dissolution effect and stability; and the Kaixinsan powder meets requirements for traditional Chinese medicine powders stipulated in Chinese Pharmacopoeia 2020 edition.