Abstract: Taking the connotation of high-quality urban development as the starting point, this paper constructs an urban development quality measurement system based on the new development concepts of innovation, coordination, greenness, openness and sharing. Selecting the data of 284 cities in China from 2005 to 2018 as the sample, it uses the vertical and horizontal extension method to measure the urban development quality index. It then analyzes the temporal and spatial evolution and regional differences of urban development quality around the measurement index, and constructs an SDM model to analyze the driving role and spatial effects of the two main bodies of the government and the market on the urban development quality. The research found that: (1) At present, the overall quality of China′s urban development is showing a steady upward trend and a pattern of "strong east and weak west", and the phenomenon of uneven development is prominent; (2) China′s urban development quality has a significant positive spatial spillover effect, and cities of similar quality have spatial agglomeration characteristics; (3) The government has played a role in promoting the quality of urban development, while the market′s role in promoting the quality of urban development is not significant, and this mechanism has different effects on different quality dimensions; (4) Both the government and the market have a positive spatial spillover effect on the quality of urban development, but the test results for individual quality dimensions have a negative effect.