The structure of the four roll plate rolling machine is four roll type, with the upper roll as the main transmission. The output gear of the reducer meshes with the upper roll gear to provide torque for rolling the plate; The lower roller performs vertical lifting and lowering motion, which is obtained by the hydraulic oil in the hydraulic cylinder acting on the piston to clamp the plate, and is hydraulic transmission; There are side rollers on both sides of the lower roller, which tilt along the frame guide rail and are driven by a screw and worm gear; The advantage of this machine is that the pre bending and rounding of the sheet ends can be carried out on the same equipment.