The invention provides a laser pipe cutter. The laser pipe cutter comprises a lathe assembly. A lathe main body is in a longitudinal shape and comprises a first longitudinal arm part, a second longitudinal arm part, and a bottom plate which is located at the bottom and connected with the first arm part and the second arm part, wherein the first arm part and the second arm part are arranged oppositely; the first arm part and the second arm part are each formed by welding an outer wall bent part and an inner wall bent part; the outer wall bent parts are internally provided with a plurality of first reinforcing ribs; and the inner wall bent parts are internally provided with a plurality of second reinforcing ribs. The lathe main body and a gantry assembly are welded through a metal plate bent part, and reinforcing rib plates are evenly distributed in the middle, the overall rigidity is improved, the stability is good, deformation is not liable to occur, and the cutting speed and cutting precision are obviously improved; and the whole machine is integrated, the occupied space is small, the cutting area is closed, and cutting waste gas treatment measures can be implemented easily.