Introduction  The mangrove ecosystem has a high carbon sequestration capacity and is an important part of the global carbon cycle. Exploring its carbon sink potential can promote the mitigation and adaptation to climate change, providing a potential marine solution for China's carbon peak and carbon neutralization.

  Method  In this study, the methodology of mangrove blue carbon assessment was studied to estimate the carbon reserve and carbon sink potential in Guangdong Province. The carbon reserve in mangroves in Guangdong Province was about 3 222.035 kt C, of which the carbon reverse in vegetation was about 1 094.465 kt C and the carbon reserve in soil was about 2 127.57 kt C. Among different mangrove communities, the vegetation carbon reserve of Aegiceras corniculatum was the highest, reaching 1 508.931 kt C, followed by Avicennia marina, Kandelia obovata and Sonneratia apetala, with carbon reserve of 1 508.931 kt C, 859.115 kt C, 193.296 kC and 660.693 kt C respectively.

  Result  According to the " Special Action Plan for Mangrove Protection and Restoration (2020-2025)", by 2025, 55.00 km² of mangroves will be planted in Guangdong Province, and the carbon sink potential can increase by 36.171 kt CO₂-e ~99.891 kt CO₂-e, with great carbon sink potential.

  Conclusion  This study can provide scientific basis for the afforestation of mangrove carbon sink in Guangdong Province, and is of great significance for China's carbon peak and carbon neutrality cause.