In order to maintain the high required surface smoothness of the mirror roll surface, a protective layer will be added to the surface of the mirror roll, but the protective layer is easy to melt under high temperature, so the mirror roll must maintain a low working temperature when it is used. However, when the mirror roll is used for rolling, heat will inevitably be generated under extrusion and friction, which will cause high temperature on the roll surface. Therefore, it is necessary to take cooling measures on the roll surface to maintain the low temperature on the mirror roll surface. Thus, the service life of the roller can be extended and the overall quality of the product can be guaranteed.