Box girder positioning temporary supporting seat and positioning construction method of box girder

The invention discloses a box girder positioning temporary supporting seat and a positioning construction method of a box girder. The supporting seat comprises a steel grit top, a base and a steel base plate, wherein the base is positioned below the steel grit top; the steel base plate is positioned above the steel grit top; the steel grit top comprises a cylinder body and a piston which is matched with the cylinder body; the cylinder body is arranged on a positioning supporting seat; a sliding friction pair is arranged between the positioning supporting seat and the base; a part of the cylinder body is filled with steel grit; and the steel base plate is spread on the top upper part of the piston. In positioning supporting seat-based box girder positioning construction method, the box girder is pre-compressed, so that the temporary support seat of the box girder is replaced by a permanent supporting seat. Based on initial erecting and positioning of a suspended working platform, the box girder is positioned a