The invention provides a preparation device and method for lead dioxide electrodes. The device comprises an electrolytic cell, an anode net, porous titanium and a cathode plate. The electrolytic cell is used for containing electrolyte, the anode net is suspended in the electrolytic cell through an anode lead and completely immersed in the electrolyte, the material for forming the anode net is titanium, and a tin antimony oxide layer is formed on the surface of the anode net. The porous titanium is arranged on the anode net to serve as an anode, a tin antimony oxide layer is formed on the surface of the porous titanium, and the porous titanium is completely immersed in the electrolyte. The cathode plate is suspended in the electrolytic cell through a cathode lead and located over the porous titanium on the anode net and is parallel to the anode net, and the cathode plate is completely immersed in the electrolyte. By means of the preparation device and method, the production process can be simplified, the corrosion resistance of the electrodes can be improved, and the service life of the electrodes can be prolonged.