Abstract: As China’s economy turns to the stage of high-quality development, it is of great significance to explore the relationship between scientific and technological innovation and urbanization for the realization of regional high-quality development. Taking 41 cities in the Yangtze River Delta as the research object, this research constructs the index system of urban science and technology innovation ability and urbanization quality, uses the coefficient of variation method, coupling coordination degree model and Moran index to study the coupling coordination degree and evolution process of science and technology innovation ability and urbanization quality, and deeply investigates the key coupling subsystems and elements. The results show that: （1)Urbanization in the Yangtze River Delta has undergone an evolutionary process starting from the core cities, extending along the transport arteries and eventually becoming pan-homogeneous;(2)The process of science and technology innovation lags behind the urbanization process, but the spatial and temporal evolution patterns of the two show a high degree of process fitting. The spatial spillover effect of the coupled development of science and technology innovation and urbanization gets enhanced with the increase of the level of coupled and coordinated development. The increase of science and technology innovation capacity is more crucial to the coupled and coordinated development of the two systems；（3）The coupling of science and technology innovation and urbanization has significant stage characteristics and shows spatial divergence over time. The coupling point changes over time and focuses on the social development gradually, which is the key to the coupling of science and technology innovation and urbanization. The study points out that paying attention to the social development construction of urbanization, the construction of regional innovation diffusion channels, the regional social interoperability, and the discovery of coupling points for the coordinated development of science and technology innovation and urbanization based on process fitting will help improve the level of coordinated development of science and technology innovation and urbanization.