Large lifting platform for vertical mounting process

The utility model relates to a large lifting platform for a vertical mounting process. At present, the defects of high working strength, huge danger, and low working efficiency are generated when operations of rotor shaft welding of steam turbine, cylinder assembly of gas turbine and the like are carried out by adopting a manual scaffolding mode. The large lifting platform is characterized by comprising a main platform, four stand columns, a vertical guider, a driving unit, a lifting type positioning device, a transmission system, a workpiece trolley, an auxiliary lifter and a chain-scission protection device, wherein the main platform is square and provided with a central hole, the four stand columns are arrayed in a square structure and matched with the main platform, the transmission system is arranged on the stand columns and connected with the driving unit, the vertical guider and the chain-scission protection device are both arranged in the stand columns, the main platform and the lifting type positioni