Disclosed is a submerged arc furnace capacitor. A capacitor is mounted in a shell; the space between the shell and the capacitor is filled with resin; the capacitor consists of a substrate, a film-coated electrode plate and a gold-sprayed electrode plate; the film-coated electrode plate is arranged on the upper surface of the substrate; the gradually-changed sheet resistance metalized film gold-sprayed electrode plate is arranged on the lower surface of the substrate; and the two ends of the gold-sprayed electrode plate are connected with wires. The processing process of the submerged arc furnace capacitor comprises the steps of a, performing film coating on the upper surface of the substrate to form the film-coated electrode plate, and adopting a gradually-changed sheet resistance metalized film on the lower surface of the substrate to form the gold-sprayed electrode plate; b, leading a gummed wire lead from the surface of the gold-sprayed electrode plate; and c, putting the capacitorinto the shell, and filling the space between the capacitor and the shell with resin. The 120uf-400V submerged arc furnace capacitor disclosed in the invention has high dielectric insulating intensity, high dielectric constant, and high inrush current and overvoltage resistance, so that relatively high capacitance value and voltage resistance value within the same volume of the capacitor are ensured; and by virtue of the unique gold spraying process, a larger contact area is realized between the film-coated electrode plate and the gold-sprayed electrode plate of the capacitor, so that higherinrush current can be withstand, and low heating amount and high self-healing property and capacitance value stability are achieved.