Abstract: The Jiudingshan Provincial Nature Reserve in Sichuan is located in one of the mountainous regions, which are the transition areas from the Qinghai-Tibet Plateau to the Sichuan Basin. The mountains are tall and climb from 700 m to nearly 5 000 m. The vertical habitat changes significantly, which breeds abundant medicinal plants resources. Totally 239 species of medicinal plants belonging to 201 genera and 95 families were found in Jiudingshan Nature Reserve. In term of species and genus diversity, there were more larger families (over 21 species), accounting for 26.32% of the total families. The middle families (6~10 species) were relatively fewer, accounting for 10.53% of the total families. The largest genera (over 21 species) had obvious advantages in quantity, accounting for 46.7% of the total number of genera. In term of the diversity of life forms, herbal medicinal plants (145 species) were dominated, accounting for 60.67% of the total species. Our study showed that Jiudingshan Nature Reserve was rich in species of medicinal plants, with various types of growth types and functions, which had great valuables for scientific research, protection and utilization.