【Objective】Rapid increase in the concentrations of greenhouse gases leads to an increase in global warming. The coastal wetland ecosystem has been identified as an important place to fix atmospheric carbon dioxide because of its powerful carbon sink function. Thus, this study aimed to quantitatively assess the temporal and spatial changes of carbon storage in coastal wetlands in China, explore its influencing factors, and augment current global warming management practices. 【Method】Remote sensing data preprocessing, vegetation index calculation and land cover type extraction were carried out based on the data of Landsat atmospheric correction surface reflectance from 1987 to 2020 provided by Google Earth Engine, and then the carbon density data of coastal wetlands in more than 30 literature were collected. Combining remote sensing quantitative inversion with the life zone method, the soil carbon reserves and biomass carbon reserves of coastal wetlands in China were calculated to research the temporal and spatial dynamics of carbon reserves in coastal wetlands in China over 30 years. 【Result】The results showed that: (1) Saltmarsh wetlands were mainly distributed in the northern coastal area, tidal flats in the eastern coastal area, and mangrove wetlands in the southern coastal area; (2) The spatial distribution of carbon density of coastal wetlands in China was quite different. Also, the maximum biomass carbon density, soil carbon density and total carbon density all existed in the region of Shankou mangrove national nature reserve. The values of maximum biomass carbon density, soil carbon density and total carbon density were 220.21 t·hm^-2, 130.46 t·hm^-2, and 350.46 t·hm^-2, respectively. Comparatively, the carbon density of coastal wetlands in southern coastal wetlands was significantly higher than that in northern and eastern coastal wetlands; (3) It was observed that the total carbon storage of coastal wetlands in China showed a decreasing trend as a whole, and its change trend was consistent with the soil carbon reserves. The biomass carbon storage had an increasing trend, with the maximum value of 5.02 Tg, and the soil carbon storage decreased first and then increased, with a maximum value of 35.54 Tg. Also, the total carbon reserves in the northern coastal region and eastern coastal region were greater than that in the southern coastal area. In addition, biomass carbon storage in the northern coastal region showed a decreasing trend, while biomass carbon storage in the eastern and southern coastal areas showed an increasing trend. The soil carbon storage in the northern coastal area, the eastern and southern coastal areas all had a decreasing trend. 【Conclusion】The results estimated in this study are comparable with those published in previous literature. Climate, vegetation and land-use change lead to a decrease in carbon storage in a coastal wetland. Human activities dominated by reclamation are the main factors affecting the dynamics of carbon storage in coastal wetlands. This paper provides a theoretical basis for effectively evaluating the carbon sequestration capacity of coastal wetlands, Also, it outlines suggestions for emission reduction, guidelines for increasing carbon sequestration measures, guides for coping with climate change, and decision support for coastal wetland ecosystem management and ecological restoration of degraded wetlands in China.