There was abrasion on the bottom match surface of the hot Rough-rolling mill which leads to the large deviation of stiffness on both sides of rolling mill in Tangshan Iron and steel 1810 hot strip product line. The problem caused some defects in the slabs such as deviation, horizontal deviation, sickle, narrow and so on. Due to the restriction of production rhythm, the production line can"t be shut down for a long time to repair the worn surface by traditional repair methods. Thus, the composite surface is used for repairing the bottom surface of the Rough-rolling mill. Time is saved effectively, Meanwhile, the repaired surface can withstand water erosion and avoid two times of corrosion and abrasion. After repair, the installation size is re-measured by laser tracker. The elevation and level meet the installation requirements of the drawings, and work normally after being put into operation. After repaired, the compression resistance and impact resistance of the bottom surface reached the composite design requirements, and the rigidity and rolling level required by the production process can be achieved..