High precision, fast speed, narrow slit, minimum heat affected zone, smooth cut surface and no burr. The laser cutting head does not come into contact with the surface of the material and does not scratch the work piece. The slit is the narrowest, the heat affected zone is the smallest, the local deformation of the work piece is very small, and there is no mechanical deformation. It has good processing flexibility, can process any pattern, and can cut pipes and other profiles. Non-deformable cutting can be performed on materials of any hardness such as steel plates, stainless steel, aluminum alloy plates, and hard alloys.