Abstract: To further understand the abandoned coal mine in species diversity and the status of environmental pollution, this study is based on the investigation of the tree species of 34 abandoned coal mines in Baili Rhododendron Nature Reserve in Western Guizhou, set up 5 non coal mines as control. Species diversity index, richness index, evenness index and dominance index were used to analyze the species diversity and evaluate the pollution status of abandoned coal mine. The results showed that there were 24 pioneer tree species, belonging to 20 families and 24 genera in 34 abandoned coal mines, the tree species is significantly lower than that of non coal mines. Forming the dominant tree community of Betula luminifera, Populus tomentosa and Broussonetia papyrifera. The species diversity of abandoned coal mines was low, and the local sample land was high, which would be related to the altitude, slope, abandoned years and human interference. The evaluation on the pollution of abandoned coal mines based on diversity index showed that the environmental pollution of most abandoned coal mines was between medium pollution and heavy pollution.