This study investigates the response of plant diversity in the high-altitude lakeside wetlands of Mang Shan to environmental factors. It not only helps in understanding the adaptive strategies of wetland plant communities to environmental changes but also holds significant value for the protection of local rare and endangered wetland species. In this study, methods such as Hierarchical cluster analysis, Canonical Correspondence Analysis (CCA), and Pearson correlation analysis were used to analyze 30 plant community plots in the study area, exploring the relationships between plant community diversity and environmental factors (soil and water). The results indicated that the plant communities in the Lang Pan Lake national important wetland were categorized into four groups: Ass.Carex filicina+Caldesia grandis, Ass.NympHaea tetragona+Brasenia schreberi, Ass.Caldesia grandis+Scirpus triangulatus, and Ass.Brasenia schreberi+Caldesia grandis. Among these groups, Ass.Brasenia schreberi+Caldesia grandis exhibited the lowest Patrick's richness index and Pielou's evenness index, while had the highest Simpson's diversity index, with the Ass.Caldesia grandis+Scirpus triangulatus showing the opposite trend. The diversity of wetland plant was significantly correlated with soil exchangeable potassium and water depth and also significantly correlated with water quality ammonia nitrogen. Water depth and soil exchangeable potassium are identified as the primary factors influencing the distribution pattern of wetland plant communities. A significant correlation between community diversity indices and environmental factors, the species richness index of the community exhibited an initial increase followed by a decrease with increasing water depth, while the species evenness index showed a negative correlation with water quality ammonia nitrogen concentration. The study aims to uncover the ecological relationship between plant community species diversity and environmental factors in the Lang Pan Lake national important wetland, providing a theoretical basis for the conservation of rare wetland species and the maintenance of wetland ecosystem stability.