The invention discloses a method for smelting a lead-bismuth concentrate in an oxygen-rich side-blown duplex furnace, belonging to the technical field of smelting bismuth concentrates. The method comprises the steps of preparing raw materials, and smelting in the oxygen-rich side-blown oxidation-reduction duplex furnace to directly produce a crude bismuth alloy. According to the method, scrap iron is not required to be added, so that the production cost is low; the concentration of SO2 in flue gases generated from oxidizing smelting reaches 10 to 25 percent, and the SO2 can be recycled to prepare acid, so that the problem of environmental pollution caused by the flue gases is solved; and the oxidation-reduction duplex smelting ensures that the direct yield of bismuth is greatly promoted.