Wetlands play a pivotal role in global carbon sequestration. Changes in soil organic carbon pools, especially the stability of organic carbon fractions, largely determine whether wetland ecosystems act as carbon sources or sinks, which induce significant impacts on global climate change. Understanding the turnover process and stability of soil organic carbon is crucial for enhancing soil carbon sequestration and maximizing potential of ecological carbon sink in wetlands. Here, we reviewed the turnover and stability of soil organic carbon in wetlands by summarizing research hotspots and findings from the aspects of organic carbon sources, sequestration mechanism, and fractions. We also highlighted the contribution of organic carbon fractions to soil carbon stability, and summarized the factors affecting soil organic carbon stability. Firstly, we summarized the soil carbon cycle processes driven by biogeochemistry in wetland ecosystems, including carbon input, organic carbon sequestration, and carbon output. Quantitative studies on soil carbon turnover in wetland ecosystems, particularly those involving external organic matter input, microbial autotrophic carbon fixation, and water-soluble organic carbon output, remain unclear. Secondly, we summarized the stability and turnover rates of soil organic carbon fractions in wetlands, introducing dissolved organic carbon, microbial-derived organic carbon, particulate organic carbon, mineral-associated organic carbon, and iron-bound organic carbon. Finally, we found that the stability of soil organic carbon in different types of wetlands was influenced by a combination of biotic and abiotic factors, climate change, and human activities. It is suggested that future research should further quantify the differences in the source, turnover, and stability of soil organic carbon fractions in different types of wetlands, in order to provide a scientific reference for improving the carbon sequestration potential of wetlands and realizing the role of terrestrial ecosystems in carbon sequestration and sink enhancement.