Abstract: In the paper, based on InVEST and GIS models, we explore the spatial-temporal evolution pattern of carbon storage in the coastal area of Beibu Gulf in Guangxi from 2000 to 2020. The results show that: (1) During 2000-2020, the land use type will change dramatically, and the cultivated land area will decrease by 5.94%, Construction land area increased by 103.58%, the change of forest area was d relatively small, only increasing by 1.2%. Over the past 20 years, 13.65% of the land has been transferred. (2) The carbon reserves in the study area in 2000, 2005, 2010, 2015 and 2020 were 21.66×10⁶ t, 21.71×10⁶ t, 21.77×10⁶ t, 21.67×10⁶ t and 21.75×10⁶ t, respectively, showing a band growth trend. The total increase is 9.22×10⁴ t. The main factor in the variation of carbon storage is the conversion between different land types, with forested land bing the most important carbon store in the study area. (3) From the perspective of global spatial correlation, carbon storage in the five periods showed a certain spatial convergence and agglomeration phenomenon. From the local spatial correlation, it can be seen that high-high clustering areas account for 27% to 38% of the research area, mainly distributed in the 100000 Dashan area of Fangchenggang and the surrounding area of Wufeng mountain in Qinzhou, The low-low agglomeration area accounts for 5.5% to 8.9% of the research area, mainly distributed in the towns of Qinzhou、Beihai and Fangchenggang city, with large population and large construction land area. The results provide data support for the implementation of the national “dual carbon” strategy, the measurement of existing carbon stocks and carbon sinks, and the promotion of carbon peaking and carbon neutrality.