In order to solve the problem of the floristic complexity and their diversity distribution pattern in the southern slope of Tianshan Mountain in Xinjiang, taking the wild seed plants in the middle sections of southern slope of Tianshan Mountain as research object, using the field investigation of plants and existing species data, by the mathematical statistics and geostatistics methods, based on the theory of plant taxonomy，floristic geography and plant ecology, the floristic characteristics and floristic vertical distribution pattern of wild seed plants and the key environmental factors affecting species diversity were studied, the evolution of the flora, the spatio-temporal distribution, and the relationship with environmental change were clarified. The relationship between species richness, climate environment gradient, species evolution and migration factors were revealed. The results will enrich the flora theoretical research in Tianshan Mountain, and provide the scientific basis for regional resource protection and development.