An annual ring analysis, relative growth equation method, and carbon/nitrogen analysis assay were used to determine the ecosystem carbon stocks (vegetation and soil) of five typical types of primitive swamps (Swamp Swamp-C, Shrub Swamp-G, Larix olgensis-Sphagnum magellanicum swamp-LN, Larix olgensis-moss swamp-LX, and Larix olgensis-Carex schmidtii swamp-LT) in the transitional zone of the wetland in the temperate zone of Changbai Mountain. The results showed that ① The vegetation carbon stocks of the five natural swamp types were(3.18±1.70)-(112.2±18.3) tC/hm², which increased gradually along the transitional zone. The conifer forest swamps had significantly higher values than did C and G by 12.2 and 34.3 times, respectively, G was higher than C by 0.6 times, and LX and LT were significantly higher than LN by 0.3 and 0.6 times; ② The soil carbon stocks of (296.3±42.2)-(824.50±50.79) tC/hm² declined along the environmental gradient of the transitional zone, C was significantly higher than that of G and the coniferous forest swamps by 30.8%-178.3%. Coniferous forest swamps were lower by 38.7%-112.8%, and LN and LT were significantly higher than LX 32.8%-53.4%; ③ The ecosystem carbon stocks of (408.42±57.53)-(827.52±50.96) tC/hm² also showed a decreasing trend along the transitional zone, C was significantly higher than G and coniferous forest swamps by 30.2%-102.7%, and G was significantly higher than that of coniferous forests. Marsh was higher by 21.5%-55.6%, and LN and LT were significantly higher than LX by 18.8%-28.0%; ④ The net primary productivity and annual net carbon sequestration of vegetation in the five swamp types were distributed at (5.74±0.08)-(10.98±1.67) t hm^-2 a^-1 and (2.44±0.03)-(5.17±0.83) tC hm^-2 a^-1, of which, the net primary productivity of LX and LT was significantly higher than that of C, G, and LN by 61.2%-91.3% and 34.5%-59.6%. In terms of annual net carbon sequestration of vegetation, the coniferous forest swamp types were significantly higher than those of C and G by 28.7%-111.9% and 19.4%-96.6%. That is why the net primary productivity and annual net carbon fixation of the five natural marsh types in Changbai Mountain show a stepwise increasing trend along the environmental gradient in the transitional zone of wetlands. However, only LX and LT reached the average carbon fixation of land vegetation and global terrestrial vegetation in China. Therefore, the long-term carbon sink effect of the Changbai mountain marsh swamps and shrub swamps is stronger than that of forest swamps. We should protect and restore swamps and shrub swamps in our wetland carbon sink management practices.