The invention discloses an elastic hanger for construction of a main girder of a long-span arch bridge, the arch rib is used for connecting with the boom on the boom area in the span of the arch rib to complete the construction of the main beam in the boom area in the span. The working platform comprises a plurality of support rods arranged at intervals along the longitudinal direction of the bridge, and two ends of each support rod are respectively connected with the boom, and the boom in the area with the boom in the middle of the span is used as an elastic support connection part of the working platform, so as to save materials and ensure the stability of the working platform. Connecting plates are connected between two adjacent supporting rods, all the connecting plates are located inthe same horizontal plane, and each connecting plate is ensured to be located in the same horizontal plane by adjusting the length of the boom and the working platform, so as to form a stable passagefor convenient construction of the constructors. After the working platform is erected, the construction of the main girder can be completed, so as to realize the rapid construction of the concrete main girder of the long-span half-through arch bridge.