Abstract:in this paper, the medium span continuous steel box girder bridge in cold area is designed according to 7.5cm asphalt concrete pavement scheme and 10cm cement concrete + 10cm asphalt concrete composite pavement scheme respectively, the change law of steel consumption index of steel box girder with bridge span and box girder height is analyzed, and the change of steel consumption index of steel box girder after composite pavement is adopted for steel box girder bridge in cold area is studied, It provides a reference for the design of medium span steel box girder bridges in cold regions.