[Objective] The species composition characteristics of the typical urban-suburban transition zone in Chengdu ring ecological zone were analyzed， in order to reveal the differences in plant diversity among different community types， management models and functional forest lands， and provide a scientific basis for the evaluation of the effectiveness of land consolidation and ecological restoration projects as well as the optimization of vegetation management. [Methods] Quadrats were established using a stratified random sampling method， and the Shannon-Wiener diversity index， Simpson dominance index， species richness index， and Pielou evenness index were used as measurement indicators to evaluate diversity. [Results] ①The urban-suburban transition zone exhibited rich plant diversity， with a total of 231 plant species belonging to 177 genera and 92 families recorded. Among them， native species accounted for 41.1%， domestically introduced species for 33.3%， and exotic species for 25.5%. In addition， the survey found 31 alien invasive plant species， predominantly herbaceous， accounting for 80.6%. ②The phytogeographic composition of seed plant genera was relatively complex， with pantropical distribution （29.4%） and north temperate distribution （18.6%） being dominant. ③The species diversity of the tree layer in mixed forests was significantly higher than that in deciduous broad-leaved forests （p<0.05）. The tree layer diversity was significantly lower in park-managed forests compared to non-park-managed forests （p<0.05）， and the species richness of the tree layer in landscape forests was significantly lower than that in non-landscape forests （p<0.05）. [Conclusion] The urban-suburban transition zone maintains a relatively high level of plant diversity， but requires heightened vigilance against the risk of invasion by alien species. It is recommended to strengthen dynamic monitoring and prioritize the selection of native evergreen broad-leaved tree species in ecological restoration.