Abstract: Since 1999, several artificial restorations on mangroves have been carried out at Yundang Lake, Xiamen, to carry out environmental management of the lake. The artificially restored mangroves are growing well showing that the ecological restoration of Yundang Lake is a successful model case. To explore the changing law of the carbon storage of artificial mangroves in different restoration periods in lagoon and obtain the basic data of carbon sink capacity of artificial mangroves at Yundang Lake (similar to a lagoon), the carbon storage (plant component carbon, litter carbon and sediment TOC) of four artificial Kandelia obovata forests coded as P10, P11, P12 and P14 in ages of 10, 11, 12 and 14 years were analyzed, respectively. Results showed that the biomass of Kandelia obovata per plant, the biomass per unit area of forest land, and the annual litter yield increased with the growth of forest age. The average carbon content of plant component increased with the forest age, with P14 (346.29 g/kg) > P12 (327.93 g/kg) > P11 (313.63 g/kg) > P10 (297.84 g/kg). The average carbon content of litter also showed a similar positive correlation with forest age, with P14 (310.28 g/kg) > P12 (300.44 g/kg) > P11 (282.28 g/kg) > P10 (279.22 g/kg). The TOC contents in sediments were 5.13-12.02 g/kg and the content decreased with depth. The TOC content in sediments increased with the growth of forest age and there were significant differences in TOC content in sediments of different forest ages at the same depth (P < 0.05). In different restoration stages of plantations, forest age has a positive impact on carbon storage and the carbon density of each component. This study is helpful to understand further the dynamic development process and ecosystem service function of artificial mangrove restoration in lagoon. It is of great scientific significance to study the carbon storage of artificial mangroves with different restoration periods for the protection and restoration of mangroves.