The retreat line of coastal buildings has been widely used internationally as a scientific and effective means of protecting and managing coastal zone development. In this paper, taking the delineation and control of coastal building retreat lines in a city in Shandong province as an example, a highprecision realistic 3D model has been built, and the retreat lines and ancillary elements of coastal buildings have been collected and edited. The core retreat lines are delineated by using the method of "basic retreat distance delineation and specific element correction". The elements are overlaid with the realistic 3D model to form a coastal zone management system. It can realize comprehensive and threedimensional display and query of elements, and provide a strong support for the refined control of coastal building retreat areas.