With the rapid development of urbanization and the proposal of "marine economy demonstration area" and "coastal economic zone", dramatic changes different from the past have taken place in the spatial structure of coastal cities. This paper selected more than 30 coastal cities of China as study object, which are typical in coastal city cluster and witness a relatively rapid development of urbanization. From the angels of external form, function layout and internal space, it discussed the general characteristics of spatial structure evolution of coastal cities in the stage of rapid urbanization. It not only contributed to the cognition of spatial development trend of coastal cities, but also provided a theoretical basis and support for the prevention of urban problems and disasters caused by spatial structure evolution.