Abstract:In this study, we took the data of the Inner Mongolia part in The Catalogue of Rare and Endangered Plants in China, The China Plant Red Book, The National Key Protected Wild Plants List (List No.1), the threatened species in The China Species Red List, the threatened species in The Red List of Chinese BiodiversityThe volume of Higher Plants (2013), The Catalogue of Rare and Endangered Plants in Inner Mongolia and Recorded Illustration of Rare and Endangered Plants in Inner Mongolia as initial data, and performed a series of revision and perfection to the name, latin name, attribution of families and genera and other problems. Eventually, we confirmed 127 rare and endangered plant species as objects of the study. During our systematic collecting and organizing of the research results and data of different scholars on relevant documents of rare and endangered plants in Inner Mongolia, we also conducted field investigation and specimen collection, the geographic distribution and features of flora of plants were analyzed in this area. Results showed that:(1) there are 127 rare and endangered plants, 103 genera and 53 families in Inner Mongolia, among which, pteridophyte covers 1 species; gymnosperm 3 families 5 genera and 9 species; angiosperm 49 families 97 genera and 117 species.(2) East and West Alashan state, Helan Mountain state and Xingan North State share more distribution of the rare and endangered plants in Inner Mongolia, each taking up to 59 species, 46.46% of the total number.(3)The vertical distribution pattern of rare and endangered plants in Inner Mongolia presents an unimodal form, with the largest amount of plant species between 1 000 and 1 600 meters. (4) Among the rare and endangered plants in Inner Mongolia, the number of Leguminosae, Compositae and Ranunculaceae species ranks top, 35 monotypic genera. (5) As for the rare and endangered plants in Inner Mongolia floristic elements, temperate distribution has the highest proportion, with ancient origin, there are many relic plants, while herb and mesophytes enjoy the largest proportion, similar to the floristic characteristics of Inner Mongolia. The aim of the research is to perform a series of revision and perfection to the list of rare and endangered plants in Inner Mongolia.