The machine adopts the four-roller structure with the upper roller as the main drive,Both upward and downward movement through hydraulic motors powered.The lower roller makes vertial movements and imposes a force on the piston through the hydraulic oli in the hydraulic cylinder so as to clamp the plate tight.Side rollers are arranged on the two sides of the lides of the lower roller,and make inclining movement along the guide rail,and provide drive through the screw,the nut,the worm and the leadscrew.The advantage of the machine is that the preliminary bending and rolling of the top ends of the plates can be conducted on the same machine.