Abstract: The effect of laser cleaning on the weldability of alloy steel was studied, and an efficient and green cleaning method was selected for the pre-welding cleaning of steel frame structure. Two kinds of rust removal methods were selected to clean the steel plate under different surface states. The analysis results show that the laser cleaning steel plate surface can meet the requirements of weld quality level I, and the advantages of laser cleaning before welding are fast and efficient, no damage to the substrate after treatment, and the substrate surface will form a hardened layer.