Abstract：Microplastics， as a kind of emerging contaminants， are ubiquitous in aquatic ecosystems worldwide， by which the environmental problem caused has become one important concern in recent years. In this study， to investigate the effect of microplastics on microbial community structure and diversity， different types of microplastics （film， debris and fiber） were collected from the water and sediment of Nanjishan wetland of Poyang Lake， and the extracted DNA were analyzed by high-throughput sequencing compared to those from the surrounding water and sediment. The results showed that the abundance and diversity of microorganisms from microplastics were significantly lower than those from the surrounding water and sediment. For bacteria， Proteobacteria， Cyanobacteria， Bacteroidetes and Actinobacteria are dominant in water and sediment， while the abundance of Proteobacteria and Firmicutes showed an obvious increase on the surface of microplastics. Meanwhile， Basidiomycota， Ascomycota and Chytridiomycota are the dominant fungi in water and sediment， while the sample of microplastics exhibited an increased abundance of Basidiomycota. Correlation network analysis predicted that Geothermobacter， Sulfuricurvum， rhizobia， Rhizobacter， MM2， Massilia， Methylotenera， Dongia， SH765B-TZT-35， Hymenbacter are the key species. This work could provide a better understanding of microplastic pollution in freshwater ecosystem and some theoretical references for lake environmental management.