The invention relates to the technical field of laser cutting equipment, in particular to a large-breadth laser cutting machine which comprises a machine tool, and a material supporting mechanism, a gantry mechanism, a cutting mechanism, position adjusting mechanisms, a heat insulation mechanism and a dust removal mechanism respectively arranged on the machine tool. The rack comprises a main crossbeam, a main longitudinal beam, a first boundary beam and a second boundary beam; the material supporting mechanism comprises a first material frame and a second material frame; the gantry mechanismcomprises a first rack, a gantry, a first motor, a second rack and a guide rail; the cutting mechanism comprises a moving frame, a second motor and a laser cutting machine, the moving frame is slidably connected with the guide rail, the second motor is arranged on the moving frame, the second motor is connected with the second rack through a gear, and the laser cutting machine is installed on themoving frame; and the two sets of position adjusting mechanisms are symmetrically arranged on the first boundary beam and the second boundary beam. The large-breadth laser cutting machine provided bythe invention can adapt to the cutting machining of large-breadth plates, and is high in precision and good in effect.