Abstract: In order to evaluate the later support effect of reservoir immigrants under the background of common prosperity scientifically, taking the reservoir migrants of Dongshan Village in Wuning County, Jiangxi Province as the research object.An evaluation index system for the later support effect of reservoir resettlement was constructed by screening 56 indicators, and the weight of each indicator was determined using the Analytic Hierarchy Process (AHP).The Fuzzy Comprehensive Evaluation (FCE) method was employed to assess the later support effect for reservoir resettlement in Jiangxi Province and Dongshan Village from 2020 to 2024, The results showed that the evaluation grade of Jiangxi Province laid between average and fairly good, while that of Dongshan Village was between average and good.The evaluation scores of Dongshan Village from 2022 to 2024 were significantly higher than those of Jiangxi Province.Dongshan Village had a relatively low evaluation grade in social security level, so more support should be provided for elderly resettlers.Jiangxi Province had a relatively low evaluation grade in the industrial development level of resettlement areas, more guidance and capital investment should be given to the industrial development of reservoir resettlement.