Carbon storage in forest ecosystems is one of the largest and most active components of carbon cycling in terrestrial ecosystems, its carbon storage level and carbon sequestration potential have been of great concern. Research into the spatial distribution characteristics of carbon storage and carbon density in forest ecosystems plays an important role in the evaluation of carbon sequestration potentials and healthy forest management. Forest vegetation carbon,soil organic carbon,forest litter carbon and dead tree carbon are the four main carbon pools in forest ecosystems. Based on the latest distribution data of forest resource inventory and field sample-plot survey information, the carbon storage and spatial distribution characteristics of the forest ecosystem in Hainan Island were studied using the InVEST model and spatial statistical analysis. The results are as follows: The total carbon storage of the forest ecosystem in Hainan Island is 338.15 TgC. The carbon storages of aboveground organisms, belowground organisms, litterfall, and soil are 85.12, 18.73, 2.90 TgC and 231.40 TgC, with 25.17%, 5.54%, 0.86%, and 68.43%, respectively. The average carbon density of forest ecosystem in Hainan Island is 147.66 MgC/hm², of which 37.17, 8.18, 1.27, and 101.04 MgC/hm² for aboveground organisms, belowground organisms, litterfall, and soil, respectively. The carbon storages of forest ecosystems in different cities and counties range from 8.55 TgC to 35.40 TgC, with the highest in Qiongzhong County. Among different vegetation types, rubber forests show the highest carbon storages, accounting for 27.72% of the total carbon storages of forest ecosystems across the Island, while the tropical montane rainforests possess the highest carbon density with 249.64 MgC/hm². Regarding the altitudinal gradient, the carbon density of forest ecosystems shows an increase followed by a decrease, and the highest carbon density occurs within 600-1300 m above sea level, and the carbon density ranges from 200.37 MgC/hm² to 228.86 MgC/hm². The spatial distribution of carbon storages of forest ecosystems in Hainan Island has a significantly spatial aggregation (P<0.01), showing a pattern of high in the middle and low in the surroundings. In the future, we should strengthen the protection and restoration of natural forest resources, achieve scientific management of forests, and optimize the stand structure to realize carbon sequestration and sink enhancement of forests.