The invention relates to a one-step copper smelting technology and a device thereof. The interior of a furnace body is divided into three zones, namely a smelting zone, a blowing zone and a refining zone, by a retaining wall; and two rows of spray guns which are arranged in a staggered manner and have an included angle with a vertical line are arranged at the bottoms of the zones; return dust is mixed and then added into mixed copper concentrate and a solvent through a charging opening of the smelting zone, oxygen-enriched air is sprayed through the spray guns to carry out self-heating smelting, to generate copper matte; the spray guns in the blowing zone spray oxygen-enriched air so as to blow copper matte into crude copper and slag; the spray guns in the refining zone supply oxygen-enriched air for oxidization, and supply natural gas as a reductant for reduction, and the generated anode copper with high purity is interruptedly discharged form a copper discharging opening, so that the low-altitude pollution problem caused by SO2 can be solved, the operation environment can be greatly improved, the utilization rate of sulfur and heat can be obviously increased, and further the economic benefits can be increased further; in addition, the invention provides a one-step copper smelting technology which is more advanced, shorter in flow, lower in investment, lower in comprehensive energy consumption, higher in recovery rate, and better in comprehensive utilization in comparison with the existing continuous copper smelting technology.