Abstract: In order to select Sargassum thunbergii which had high carbon sequestration rate, to guide artificial seed breeding and farming, and to increase fisheries carbon sinks response to global climate change, wild S. thunbergii from Jiaojiang Taizhou, Pingtan Fujian, Dongtou Wenhou and Shengsi Zhoushan were cultivated in Dongtou. The length and weight were determined, the growth rate and carbon sequestration rate were analyzed. The result showed that: the maximum length and weight of wild S. thunbergii was from Dongtou Wenhou, the length of different sources had very significant difference (P＜0.01), the weight of different sources had significant difference (P＜0.05). It was found that factor S, which was the ratio of fresh weight to length of a single algae, the maximum S value of wild S.thunbergii was from Pingtan Fujian, had significant difference (P＜0.05) among different sources. The maximum carbon sequestration rate by standardized conversion was Dongtou Wenhou (0.86 t C/(hm2·a), and comparable with the forest. Therefore, people should vigorously spread the local S.thunbergii germplasm, develop artificial breeding technology and protect the wild S. thunbergii resources in Wenzhou.