A polishing device configured to polish a glass substrate is disclosed, including a polishing wheel fixedly arranged, a cooling pipe, and a movable platform. The polishing wheel has an outer peripheral polishing surface, the glass substrate is placed on the platform and is driven by the platform to move so as to make the outer peripheral polishing surface polish the predetermined polishing surface of the glass substrate; the polishing wheel further has a chamber, and the cooling pipe containing a coolant is disposed in the chamber to decrease a temperature of the chamber and then to make temperatures of the outer peripheral polishing surface and the predetermined polishing surface during polishing is lower than a preset temperature. The disclosure solves the problem of high polishing temperature of the polishing wheel and the glass substrate, thereby enhancing the service life of the polishing wheel and the yield of the glass substrate.