Abstract: Species richness, Shannon index to characterize alpha (α) diversity, Bray-curtis index to characterize beta (β) diversity and distance matrix multiple regression and variance decomposition methods were used to explore the relationship between α diversity and β diversity of seed plants in Dali Cangshan and environmental factors such as annual mean precipitation, annual mean temperature, slope, aspect, rock type and soil type. Results show that the species richness and genus richness distribution pattern of seed plants in Cangshan area are the same, and the richness has a single-peak curve relationship with altitude. The maximum abundance is about 2 000 m above sea level, and the maximum richness of species is about 2 500 m above sea level. There is a significant correlation between α diversity and β diversity and various environmental factors. For α diversity, the annual relative precipitation and rock type combination have the highest relative interpretation ability, and the common interpretation ratio is 85%. The most interpretative ability of β diversity is the annual average precipitation, the interpretation rate is 83%, the interpretation rate of lithology is 78%, and the interpretation rate of the 2 is 88%. Therefore, this study indicates that the diversity of seed plants in the study area is mainly formed by the combination of climate, soil and topography. Regardless of the α or β diversity, the explanatory variables of environmental variables account for the majority, so it is speculated that the niche effect has an important impact on the formation and maintenance of the community in this area.