Abstract: Mangroves are the most important coastal blue carbon sinks. The accurate estimation on the carbon sequestration capacity of plant communities would guide the mangrove conservation, afforestation and management. This study investigated the vegetation carbon stocks of dominant mangrove communities, which were Avicennia marina, Kandelia obovata, Sonneratia caseolaris, and Sonneratia apetala in Futian Nature Mangrove Reserve in Shenzhen, Guangdong Province of China. Vegetation carbon stock consisted of living trees (aboveground and belowground biomass), understory, pneumatophore, standing dead trees, fallen dead trees and litter in these communities. The net primary productivity (NPP) was calculated from the litterfall and incremental growth in the same year of each community. Our results showed that the vegetation carbon stocks for A. marina, K. obovata, S. caseolaris, and S. apetala communities were 28.7, 127.6, 100.1, and 73.6 t C·hm^-2, and the NPP were 8.75, 7.67, 9.60, and 11.8 t C·hm^-2·a^-1, respectively. Therefore, acting as urban forests, Futian mangroves in Shenzhen assimilated about 4000 t CO₂·a^-1. These results provided guidance for mangrove blue carbon assessment, and theoretical basis for the construction of coastal carbon sequestration forests in China.