Abstract: The early constructed CBDs in China usually have a relatively single function, small development scale, and lack of systematic connections. The lack of connection will greatly limit the region to exert higher comprehensive benefits. Starting from the related theories of underground connection, this article summarizes the principles,modes, types of facilities, and temporal and spatial scope of underground space connection. Taking Lujiazui CBD as an example, it explores the urban renewal design method of the early CBDs based on connection theory.