Based on the survey of the resettlers from the Three Gorges region in Jiangsu and Anhui provinces, this paper analyzes the social integration of resettlers under the two modes of centralized resettlement and decentralized resettlement by using the interview method. The study found that there were significant differences in economic integration, cultural integration, social relationship integration and identity between the two resettlement modes. The decentralized resettlement resettlers lack the support of the original social network at the initial stage of relocation, and their sense of relative deprivation and special citizen mentality are stronger, the failure of interaction with local people has a long-term impact on the psychology of resettlers; Compared with the decentralized resettlement, the immigrant subculture formed in the centralized resettlement areas hinders cultural integration. These factors lead to the difference of social integration effect between the two resettlement modes. In the follow-up support period, we should carry out more community activities, conduct more visiting and comforting, and strengthen the implementation of support to promote the social integration of resettlers.