Abstract: The high-quality development of Yangtze River Delta urban agglomeration has important demonstration value. Tanking 41 cities in Yangtze River Delta urban agglomeration as samples with relevant data from 2014 to 2018, this paper constructs a high-quality development evaluation system by indicators selected from three dimensions: economic operation, social progress and ecological sustainable level, and uses entropy method to calculate the weights. The results show that: the weight of each dimension of high-quality development in Yangtze River Delta urban agglomeration is unstable, the weight of economic operation is reduced to some extent, the overall level of high-quality development is volatile, the trend of high-quality development varies from city to city, regional differences are obvious, the high-quality development of the cities surrounding Shanghai is significantly higher than that of other cities, and the trend of polarization is prominent. Finally, the paper puts forward some suggestions: control the whole situation and always adhere to the concept of coordinated development; adjust measures to local conditions and gradually optimize the regional development model; cooperation and sharing to accelerate the integration of Yangtze River Delta.