Evaluation of the effectiveness of poverty reduction is a hot topic in international poverty reduction strategy research in recent years, and it is also a key issue for China to deepen and improve the quality of poverty reduction in the future. Based on the criteria of "rural poor people have no worry about food and clothing and have access to compulsory education, basic medical services, and safe housing", this study constructed an index system for evaluating the effectiveness of poverty reduction, which covers economic, demographic, social, and green development dimensions that include 12 indexes. Entropy weight and fuzzy set methods were used to reveal the effectiveness of poverty reduction in 126 cities of the Yangtze River Economic Belt, and the spatial autocorrelation theory was introduced to analyze the spatial differentiation and evolution characteristics of poverty reduction effectiveness in the region. The results show that: 1) During 2011 and 2017, the Yangtze River Economic Belt as a whole achieved remarkable results in poverty reduction, but there were obvious spatial differences among different areas, and there was great potential for poverty reduction and improvement in the upper reaches of the Yangtze River Economic Belt. 2) During the study period, the Moran's I of the cities was greater than 0 and increased year by year, the effectiveness of poverty reduction in the cities showed a positive spatial correlation and the agglomeration characteristics steadily enhanced. 3) There were regional differences in the local indicators of spatial association (LISA) value of the poverty reduction effectiveness index during the study period, and the local spatial autocorrelation between the upper and the middle reaches was more significant. Especially in the concentrated contiguous severe poverty areas, it showed the correlation characteristic of continuous agglomeration. The research results can provide a reference for promoting sustainable poverty reduction and coordinating regional economic, social, and ecological developments in the Yangtze River Economic Belt.