The ecosystem carbon storage (vegetation C storage and soil organic C storage), carbon sequestration and net primary productivity of five types of natural wetland (hassock wetland, shrubs wetland, Alnus sibirica var. hirsuta wetland, Betula platyphylla wetland and Larix gmelinii wetland) were studied by using Multi N/C 3100, HT 1300 Solids Module (Analytik Jena AG, Germany) and the sample tree analysis method in Daxing'anling of northeast China, so as to evaluate the carbon sinks of natural wetlands quantitatively and reveal the influences of environmental gradients on wetland carbon sinks. The results showed that: ①The vegetation carbon storage of five wetland types varied from (0.48±0.08) to (8.33±0.66) kg C/m², which took on rising trends along the water environmental gradient from marsh to forest;②The soil organic carbon storage of five wetland types varied from (19.21±6.17) to (38.28±4.86) kg C/m², which took on lowering trends along this environmental gradient;③The ecosystem carbon storage of these wetland types varied from (27.54±7.16) to (38.76±4.58) kg C/m², which nearly took on constant trends along this environmental gradient, and the soil C pool all dominated in five kinds of ecosystem C pool (69.7%-98.8%);④The net primary productivity (NPP)of five wetland types varied from (0.68±0.10) to (1.08±0.12) kg·m^-2·a^-1, NPP of Alnus sibirica var. hirsuta wetland was the highest, that of Larix gmelinii wetland was the lowest, and NPP of others were in the middle level, and they generally were lower than that of the temperate forested wetlands, but higher than that of the cold temperate larch forest;⑤The vegetation net carbon sequestration (VNCS) of five wetland types varied from (0.32±0.09) to (0.51±0.06) kg·m^-2·a^-1, and VNCS of Alnus sibirica wetland was the highest (which was higher than the average of global vegetation net carbon sequestration), VNCS of shrubs wetland and Betula platyphylla wetland were in the middle level (reached or approached the average VNCS of global vegetation), VNCS of hassock wetland and Larix gmelinii wetland were lowest (but slightly lower than the average VNCS of global vegetation), therefore, five types of natural wetlands all have strong carbon sink function in Daxing'anling of northeast China.