With the increasing shortage of urban construction land, there are more and more cases of planning the overlapping utilization of municipal bridge and subway line (station). Therefore, the design and research on the co-construction of municipal bridge and subway line (station) are becoming increasingly important. The influencing factors in selection, overall design and detailed design of the co-construction structure scheme are discussed and studied through a design case of a co-construction project of municipal crossing-river bridge and subway underground station. Based on the successful construction and operation of the co-construction structure, the design experience in the co-construction structure of the municipal crossing-river bridge and subway underground station is summarized in order to provide the useful design ideas and experience references for the similar projects in the future.