Changes in vegetation communities are projected to have a greater impact on the turnover and storage of carbon in coastal wetlands by affecting soil organic matter decomposition. Microbial metabolism regulates the process of organic matter decomposition in the soil. However, there is still a need for a mechanistic framework to predict the effects of vegetation changes on soil microbial metabolism. Hence, this study aimed to evaluate the changing trends of microbial metabolic limitation and carbon use efficiency under natural succession and vegetation community degradation in a wetland using soil extracellular enzyme ecological stoichiometric ratios. The results showed that microorganisms at the degradation sites experienced higher carbon limitations compared to others. Microbial carbon use efficiency at the degradation sites was significantly lower (p<0.05). A trade-off between microbial carbon limitation and carbon use efficiency was observed, as these two factors were negatively associated. Furthermore, microbial carbon use efficiency showed a strong correlation with changes in soil pH. These findings suggest that, to balance microbial carbon limitation and mitigate the adverse effects of soil pH changes, microorganisms allocate more carbon from microbial carbon use efficiency toward the production of relevant extracellular enzymes.