Currently, the outer light path of laser cutting machine mainly adapts the laser light flying path system. The laser beam from the laser generators is reflected by three or multiple reflectors before reaching the laser lens within the laser cutting head and then was spotted on the processed materials. The first reflector is fixed on the machine shell. The second reflector moves on the crossbeam along the direction of X and Y axis. The third reflector moves with the laser head toward the direction of X, Y axis. During the process of cutting, the length of light path change constantly with the movement of crossbeam and laser head.