Studies on the mechanism of wetland plant community assembly can provide an important theoretical basis for wetland ecosystem management and ecological restoration and reconstruction of the damaged wetlands. There are very abundant wetland resources in Hubei Province located in the Yangtze River Basin. In this study, we investigated main wetland plant communities by conducting the field survey and analyzed the β-diversity of wetland plant community in Hubei section of the Yangtze River Basin. The correlation between species dissimilarity of wetland plant communities and environmental distance and geographic distance, and relative contribution of environmental differences and geographic distance for accounting for community assembly were tested, using the Mantel test method and a multiple regression model based on similarity or dissimilarity matrices. The results showed that the species dissimilarity index of wetland plant communities in eight different types of wetlands in Hubei section of the Yangtze River Basin were significantly differed. The species dissimilarity indexes among wetland communities significantly were positively correlated with geographical distance and environmental differences. MRM analysis showed that environmental filtering and diffusion limitation together explained 54.72% of the community species variability index in the study area. The independent effects of the two tested hypotheses above mentioned were 22.03% and 9.98%, respectively. Our findings implied that the combined effects of environmental filtering and diffusion limitation decided wetland plant community assembly in Hubei section of the Yangtze River Basin, and in comparison to diffusion limitation, the environmental filtering had stronger effects. We argue that other factors, such as time scale and interference, should be considered in a study of wetland plant community assembly, beside spatial scale, environmental factors, and vegetation types.