Abstract: Based on three years' investigation,the medicinal plants in Shihu Provincial Nature Reserve were studied. There were about 355 species of medicinal plants belonging to 244 genera and 89 families, which accounted for 60.27%,74.62% and 91.75% of the total species, genera and families of plant resources there.There were 13 species of endangered plants under the national protection,which accounted for 7.74% of the endangered medicinal plants in China;47 species of medicinal plants under the provincial protection of Jilin;8 species of protected medicinal plants in China and 13 species of native medicinal plants in the Northeast.The medicinal plants that as a whole plant had medicinal value occupyed 39.72%,that only the roots had such value 23.10% and that only the rootstocks had such value 12.39%;antipyretics medicine and medicines for rheumatism accounted for 32.39% and 15.49% respectively.98.03% species were distributed in Korean pine broadleaved-coniferious mixed forests with the altitude of 7001 000 m. 42.86% of these species belonged to the north temperate type.The dominant families were mainly Composiatae, Rosaceae, Ranunculaceae, Liliaceae and so on.The concrete suggestions of protection and exploitation were given.