The utility model relates to a continuous steel box girder for reinforcing a soleplate on a supporting point. On the supporting point of the continuous steel box girder, the upper edge of a bridge is strained, the lower edge is pressed, the thickness of a large steel plate needs to be increased in order to prevent the local flexion of the structure, but the steel consumption of the whole bridge is increased. A longitudinal reinforced rib is respectively welded on the inner side of each of a top plate, a soleplate and webs on two sides, a shear nail is arranged on a soleplate area on the supporting point, and C50 shrinkage-free concrete is filled; and the shear nail is vertically welded on the inner side of the soleplate, the inner side bottom of the web and the longitudinal reinforced rib of the soleplate. The C50 shrinkage-free concrete is filled on the soleplate, so that the soleplate on the lower edge of the bridge is reasonably integrated with the concrete to be stressed collectively, the flexion instability problem of the steel plate on the lower edge can be solved, the thickness of the steel plate can be effectively reduced, and the consumption of the steel for the whole bridge can be reduced; the stress on a supporting seat can be effectively scattered, so that the stress of the steel plate is uniform and reasonable; and the steel box girder is used as a support, no template is needed, and simplicity in operation can be realized when the continuous steel box girder is under construction.