This study was conducted to evaluate the species composition and the use value of medicinal plants according to the experience of the Xinh Mun ethnic group at Phieng Pan border commune, Mai Son district, Son La province, from July 2019 to May 2020. The results showed that there were 362 species of medicinal plants belonging to 269 genera and 110 families of 4 phyla of vascular plants. There were 9 families with the highest number of species. The medicinal plants were differently used by the Xinh Mun ethnic to treat 19 groups of diseases. The number of plant species used for the treatment of skin diseases was highest with 77 species (21.27%). Of the parts used, leaves were most used (45.58%), followed by stems and roots with 93 and 87 species, respectively. 26 medicinal species (accounting for 7.18%) have been identified in Vietnam’s Red Data Book (2007), 18 species were listed in Vietnam’s Red List of Medicinal Plants, and 9 species were listed in the Governmental Decree 06/2019/NĐ-CP. These species had few individuals that need to have policies for conservation and development.