Phyllosphere microbiota play an important role in plant growth and survival. The Dajiuhu wetland harbours a diverse range of plant species, but the composition and functions of the leaf microbiota remain poorly understood. We analysed the structures of the phyllosphere microbiota of twelve typical plants in this wetland via 16S rRNA sequencing and evaluated the determining factors and ecological role of the leaf bacterial community. The structure and diversity of the leaf bacterial community varied among plant species. Notably, the bacterial composition of Polytrichum significantly differed from that of the other plants. The specific leaf area was positively correlated with the Chao1 and Shannon indices, whereas the leaf thickness was negatively correlated with them. Plant type, geographical location and invasiveness affected the structure of the leaf bacterial community. The core community comprised mainly Sphingomonas, unclassified_f__Alcaligenaceae and Methylobacterium-Methylorubrum. Further analysis revealed that plant invasiveness influenced the species proportion and the network relationship of leaf-associated bacteria, with invasive plants hosting higher abundances of plant pathogens than noninvasive plants. Our results suggested that leaf microbiota contribute to the ecological functions of the host plants, offering a valuable basis for utilizing microbiota to enhance plant adaptability and ecosystem stability sustainably.