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Lakes represent an important source of atmospheric methane (CH₄); however, there are few studies on which lake-dwelling invasive aquatic plants generate CH₄. Therefore, in this study, CH₄ emissions were measured using a floating chamber and gas chromatography in a subtropical lake in China. We considered four community zones of invasive plants (<i>Eichhornia crassipes</i>), emergent vegetation (<i>Zizania latifolia</i>), floating-plant (<i>Trapa natans</i>) and open-water zones. The results indicate that the flux of CH₄ emissions varied between −5.38 and 102.68 mg m⁻² h⁻¹. The higher emission values were attributed to lake eutrophication. Moreover, the flux of CH₄ emissions in the invasive plant zone was 140–220% higher than that in the open-water and the floating-plant zones. However, there was no significant difference in CH₄ emissions between the invasive plant and the emergent vegetation zones. This may be due to a higher production of plants, as well as the rapid reproductive rate of the invasive plants. Finally, CH₄ emissions were positively associated with the air and water temperature; however, the emissions were also negatively associated with water depth. Our results suggest that invasive plants enhance freshwater CH₄ emissions, thus contributing to global warming.