Abstract: The Rhododendron brevicaudatum is a rare and endangered plant peculiar to Guizhou.To explore the community structure and diversity, the species composition, faunal characteristics, life form spectrum, community structure and diversity of two R. brevicaudatum communities were investigated and analyzed by sample method.The results showed that there were 72 species of vascular plants belonging to 59 genus and 39 families in community Ⅰ,while there were 95 species belonging to 71 genus and 45 families in community Ⅱ.The distribution types of genus were mainly tropical type, and the genus in community Ⅰ and community Ⅱ accounted for 50.00% and 41.27% of the total genera, respectively.The life form spectrum was dominated phanerophyte, and the community Ⅰ and community Ⅱ accounted for 66.67% and 70.53% of the total respectively.The vertical structure of the two communities could be divided into tree layer, shrub layer and herb layer.The diameter structure（DBH≥1 cm） and the height structure of the two communities were “inverted J-shaped” or “single peak type”,with good regeneration, and the dominant species population was either growing or stable.The similarity coefficients of genus and species in the two communities were 0.368 4 and 0.201 4 respectively, and there were differences in diversity index among different communities and at different levels in the same community.The Margalef index, Simpson index, Shannon-Wiener index and Pielou index in community Ⅱ were higher than those in community Ⅰ.The Chimonobambusa angustifolia was dominant within shrub layer with inhomogeneous distribution and the diversity index was the lowest（except for Margalef index of community Ⅱ）.The community Ⅰ had less human activity and longer succession time,and it was in the late stage of succession and developed towards the apex community.In addition,the community Ⅱ was in the middle stage of succession due to frequent human disturbance.