The invention relates to a device for washing pollutants including rust spots, corrosion, oil stains and the like on surfaces of various types of metal sheet materials and particularly relates to a large-breadth laser washing machine. The large-breadth laser washing machine comprises a worktable, wherein a conveyor belt driven by a stepping motor is arranged on the worktable along the length direction of the worktable; the bottom of a supporting frame is mounted on the two sides of the worktable; a hoisting mechanism is arranged on the supporting frame; and the two ends of a hoisting transverse beam, which are arranged along the width direction of the worktable, are connected with the hoisting mechanism respectively. Therefore, the structure is reasonable and novel in design and has no grinding, non-contact and no heat effects in a washing process; in the washing process, no pollution to the environment is caused and body health of workers is not injured; a washing area is large, the efficiency is high and the washing cost is low; the distance between the device and a washing surface can be accurately controlled and the washing is uniform and has good effect.