The present invention discloses a device and method for preventing copper plating of a conductor roll in the technical field of manufacturing of copper electroplating films. A conductor roll and an electroplating anode are respectively connected to the negative output end and the positive output end of a first power source, the conductor roll and the electroplating anode electroplate a plating product flowing through plating pool bath after being electrified, and the conductor roll is connected to the positive output end of a second power source and mated with an auxiliary electrode connected to the negative output end of the second power source to realize the electrolysis of the conductor roll so that the conductor roll avoids copper deposition when electroplating the plating product. The present invention can realize the electrolysis of bath near the conductor roll on the premise of completing electroplating by the conductor roll so that the copper electroplating process and the copper electrolyzing process are balanced on the conductor roll to avoid residual copper on the conductor roll so as to improve the copper plating quality of the plating product, and the present invention does not increase the procedure of the electroplating process or affect the implementation of the electroplating process.