Invasive plants have posed a threat to the maintenance of biodiversity. Furthermore, microplastics (MPs) affect the performance and interactions of native and invasive plants. However, the impact of MPs on traits and interspecific relationships for invasive plant communities has been often ignored. Hence, we established a natural germinated invasive plant community using Flavidium bidentis soil seed banks and introduced polyethylene (PE) MPs and polypropylene (PP) MPs into the soil at the three levels (0.1%, 0.5%, and 1%). The results revealed that MPs significantly diminished the biomass and height of F. bidentis and native plants, with a weaker inhibitory effect on F. bidentis compared to native plants, indicating a potential ”Matthew effect” in invasive plant communities. Additionally, MPs decreased the root length (RL), root surface area (RSA), and root volume (RV) of invasive plant communities in most treatments. The results demonstrated a significant decrease in Richness Index in the 0.5% PE-MPs, 1% PE-MPs, and 1% PP-MPs compared to CK treatment, however, the Shannon-Wiener Index, Simpson Index, and Pielou’s Index showed no significant difference in all PE-MPs and PP-MPs treatments. The relative invasiveness index (RII) increased significantly at 0.1% MPs and 0.5% PE-MPs treatments by 50.62%, 51.04%, and 70.54% respectively compared to CK treatment, demonstrating a significant positive correlation with soil pH. PP-MPs and PE-MPs treatments could significantly affect the interspecific relationships of the invasive plant communities. Specifically, the interspecific correlation between F. bidentis and Setaria viridis was negative in CK treatment, which shifted to a significant positive correlation at 0.1% PE-MPs. Our study addresses a critical gap in our understanding of the impact of MPs on invasive plant communities and contributes insights into the management of invasive plants in wetlands.