The main bridge of Shuangbao Bridge of second Chongqing-Hunan highway is a 2 × 405 m two span continuous concrete filled steel tube (CFST) deck type arch bridge in Chongqing, with a rise-span ratio of 1/4.75. It is a catenary arch whit axis coefficient of 1.55. The arch rib adopts lattice structure with four-limb CFST rib, the width of one side arch ring is 7.5 m, and the center distance between the two arch rings is 17.5 m. The diameter of a single arch rib is 1400 mm with max thickness of 35 mm and material combination of CFTS arch is Q390 and C70. The bridge deck is integral assembled continuous composite girder with a single span of 27 m. The geological conditions are complex under the central arch skewback where karst is strongly developed, and the structure of shallow dig skewback with pile foundation is adopted as the central skewback supporting system. The superstructure is installed with suspension system, and the arch rib is lifted by large segment. The bridge is the world's largest two span continuous arch bridge and the largest span of wide four-limb CFST arch bridge, and it enriches the bridge structure forms under the complex terrain conditions and geological conditions in mountainous areas. Shuangbao Bridge is hidden in the mountains whit dual span continuous arch bridge which is quite characteristic, and will become a landscape integrating humanity and nature.