Abstract: In the context of economic globalization, urban agglomeration becomes an important foci and form of territorial development. Based on the perspectives of institutions and mechanisms, development trends, innovative industries, ecological environment, infrastructure provision, and public services, this paper establishes an index system to assess the integration levels of five urban agglomerations in the Yangtze River Economic Belt.This study analyzes how the development levels have changed across different urban agglomerations during the last decade. This paper attemptsto provide scientific references for the high-quality development of urban agglomerations.It is found that the regional integration of five urban agglomerations in the Yangtze River Economic Belt shows a decreasing trend from the downstream to the upstream areas. TheYangtze River Delta Urban Agglomerations has the highest development level, followed by the Triangle of Central China,Chengdu-Chongqing City Group, and the two regional urban agglomerations in central Yunnan Province and central Guizhou Province. For the five dimensions of regional integration, the integration levelof infrastructure development in urban agglomerations is the highest, while that of innovative industries is the lowest.In the past 10 years, there has been significant progress in the urban agglomeration integrated development, but the development content and promotion degrees differ.The middle and lower reaches of urban agglomerations focus on public services, while the upper reaches focus on infrastructure construction.This paper puts forward appropriate policy suggestions on the integrated regional development of urban agglomerations in the Yangtze River Economic Belt from perspectives of short-term improvement and institutional mechanism construction.