Combined lifting appliance, bridge girder erection machine and working method of combined lifting appliance

The invention provides a combined lifting appliance, a bridge erecting machine and a working method of the combined lifting appliance, and relates to the technical field of high-speed railway bridge construction equipment. According to the combined lifting appliance, the lifting frame serves as a main body structure, the whole combined lifting appliance can be conveniently moved by the lifting beam trolley, a box girder can be conveniently transported, the two carrying pole shafts are detachably installed in the lifting frame and symmetrically arranged at the two ends of the lifting frame in the length direction, and the two carrying pole shafts can be detachably connected with a double-line carrying pole assembly or a single-line carrying pole assembly; the double-line carrying pole assembly or the single-line carrying pole frame can be detachably connected with the hanging bracket through the carrying pole shaft according to the type of a box girder needing to be dispatched, the single-line box girder or th