The surface roughening and slotting unit adopts a frame, combined alloy cutting head, motor, air pressure device, and roller. It is suitable for using a spiral cutting set to peel and roughen the surface of the extruded board, obtaining the required surface structure to ensure the wall adhesion of the board. Using a high-speed rotating saw blade to polish rain grooves with a certain depth and width on the surface of the board, in order to increase its surface bonding performance.