Due to its fragile ecological environment and superior natural and location conditions, coastal areas are receiving extensive attention all over the world. Scientific space control is needed to ensure the harmonious development of the “human-land-ocean” system in this region. The monitoring index system is a crucial grasp of the national territory use control; it is also one of the main contents in the reform of China’s planning system in the new era. Therefore, based on the strategic idea of land–sea overall management and the concept of “life community of human, mountains, rivers, forests, farmlands, lakes, grasslands, and ocean”, this study puts forward three connotations of the index system of coastal spatial planning from the perspective of “function-structure-elements.” Then, adopting the methods of “multiple planning integration” and expert consultation and using the research idea of “setting control objectives, contents, and indicators,” an index system suitable for coastal space control is constructed. The results show that the index system puts forward 33 sub-indexes for coastal ecological space, living space, and production space and provides a basis for the high-quality development of coastal space through the restrictions and requirements on the total amount, bottom line, boundary, conversion, and quality of various spatial elements. This study can provide a basis for formulation, implementation, and later monitoring of coastal spatial planning and provide an index reference for the management of coastal areas in other countries in the world.