The invention provides a fly ash plasma melting furnace for waste incineration fly ash treatment. The fly ash plasma melting furnace comprises a furnace body, a furnace chamber, a cathode and an anode, wherein the furnace chamber is arranged inside the furnace body, the cathode and the anode are arranged on the furnace body, at least a part of the anode is positioned at the bottom of the furnace chamber, the cathode extends from the top of the furnace chamber to the position close to the bottom of the furnace chamber and is separated by a predetermined distance from the anode positioned at thebottom of the furnace chamber, a plasma arc is generated between the anode and the cathode, fly ash entering the furnace chamber is melted under the action of the plasma arc to form molten fly ash, and at least a part of the plasma arc is located in the molten fly ash. A submerged arc operation mode is adopted to replace an operation mode of a traditional plasma furnace open arc, so that the arcis not exposed in a free gasification region, and a conductive metal layer is used for preventing a refractory material working layer from being in direct contact with the molten fly ash which is strong in erosion resistance and large in component fluctuation.