The invention discloses a one-step copper smelting process and device. The device comprises a furnace body provided with a closed furnace chamber. From the bottom, the closed furnace chamber is sequentially provided with a refining area, a converting area and a smelting area from bottom to top. A plurality of first spray guns are arranged on the portions, around the refining area, of the furnace wall. A plurality of second spray guns are arranged on the portions, around the converting area, of the furnace wall. A plurality of third spray guns are arranged on the portions, around the smelting area, of the furnace wall. A plurality of fourth spray guns located below the first spray guns are arranged on the portions, around the refining area, of the furnace wall and/or the bottom. A slag discharging opening is formed in the portion, above the smelting area, of the furnace wall. A feeding port and a flue outlet are formed in the top of the closed furnace chamber. A copper discharging opening is formed in the bottom of the closed furnace chamber. The device has the advantages of being simpler in structure, durable, high in efficiency, less in investment, low in operation cost and the like; the process comprises the steps of distributing and discharging materials, carrying out smelting, converting and refining respectively, carrying out anode copper electrolysis, and treating slag and smelter off-gas, and has the advantages of being short in flow, high in adaptability, low in energy consumption, environmentally friendly and the like.