The main bridge of Shanghai Maogang Bridge is a 225 m long cable-stayed bridge with double tower parallel single cable plane steel tower and steel box girder. The bridge adopts the structural system of fixed connection of tower and beam and separation of tower and pier. A combination of orthotropic deck UHPC is adopted for the main girder bridge deck. Based on this project, the key technology of the manufacture and installation of steel box girder cable-stayed bridge is discussed.