Abstract: Small wetlands are distributed widely. However, the soil carbon stock and ecological stoichiometric characteristics of the wetlands have received little attention, which may restrict the accurate calculation of the budget of wetland carbon stock. In this study, six types of wetlands in the Tangma Reservoir watershed in southern Jiangsu Province were selected, which included river, water-level-fluctuating zone of reservoir, open-water zone of reservoir, freshwater farm, agricultural pond, and paddy field. Specifically, soil profiles of 1 m depth were collected and analyzed for soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), and the ecological stoichiometric ratio. Soil SOC, C/N, C/P and N/P were measured as 3.65±3.60~8.17±6.26 mg/g, 7.7±4.6~10.8±2.5, 18.0±6.2~34.4±16.4 and 1.9±0.5~3.1±1.4, respectively. Significant differences of soil SOC, TN, TP, C/N, C/P, and N/P among different wetlands were identified (p < 0.01). These elements were generally higher in the water-level-fluctuating zone of reservoir and paddy field, and lower in the open-water zone of reservoir, river, and freshwater farm. The soil carbon density of the six types of wetlands ranged 4.41±3.94~9.37±5.81 kg/m2, which was lower than the average of national wetlands, but at a close level to the results of coastal wetlands and eastern lake wetlands in China. The relatively higher TN and TP indicated that the wetlands had a great potential for carbon sinks.