Taking 11 cities in the coastal zone of East China Sea as the study area, the dynamic changes and correlations of the coupling and coordination of urbanization systems from 1978 to 2018 were explored based on the coupling coordination measurement model and gray correlation model. The results showed that the coupling and coordination of urbanization system in the study area exhibited a temporal phase and a spatial local high-value agglomeration. The characteristics of temporal phase were mainly manifested in urbanization speed, urbanization focus and urbanization balance. In 1978–2007, the urbanization level of each case city improved rapidly. The focus of urbanization was the optimization of industrial structure and the economic improvement, which were also the first to enter the coordinated development period with the urbanization rate. The coupling and coordination degree of urbanization system was significantly affected by a single key factor. In 2008–2018, the growth rate of urbanization tended to be flat, and the focus of urbanization began to shift to the improvement of the quality of development with “people”. The coupling and coordination between the two attributes of people’s livelihood quality and public service and the urbanization rate have been rapidly improved. Cities such as Shanghai and Xiamen, which have higher levels of urbanization, have entered the period of coordination and advanced coordination. The coupling and coordination of urbanization system was affected by multiple factors. The spatial local high-value agglomeration means that the coupling and coordination of urbanization system presented a development model with Shanghai, Ningbo, Fuzhou and Xiamen as the poles.