The Yangtze River Delta urban agglomeration，urban agglomeration in the middle reaches of the Yangtze River and the Chengdu-Chongqing urban agglomeration are the most active areas with the highest concentration of population and resources，the highest level of comprehensive development，and are the important growth poles supporting the development of the Yangtze River Economic Belt. This paper makes a comparative analysis of the general situation and the development in 2017 of the three urban agglomerations. It concludes that there are obvious regional differences in the basic situation，development stage，development level and structural characteristics among the three urban agglomerations. The problems of unbalanced and inadequate development among the three urban agglomerations and among different cities are still obvious. Moreover，the actual functional area of the three urban agglomerations is less than the planned area. Therefore，the primary task of the development for the three urban agglomerations is to promote the coordinated development of the cities within every urban agglomeration and cultivate their own functions. Then，the government should strengthen the development links between the three urban agglomerations and cultivating them as an important engine to promote the economic development of the Yangtze River Economic Zone and even China.