A concentrated oxygen jet gun for smelting steel in electric furnace features that its primary oxygen jet channel has its outer layer surrounded by a protecting system composed of fuel spray pipe, and the said protecting system composed of fuel injecting tube, secondary oxygen inlet and fuel inlet nozzle. The concentrated oxygen jet gun is arranged on the furnace wall and blows oxygen at the position 400-1000 mm above the slag line. The gas generated by burning gas or liquid fuel and secondary oxygen is used as protecting gas to keep the original impact force and the speed of primary oxygen at the distance of 800-2000 mm far from the gun. Its advantages are high decarbonizing speed, high utilization rate of oxygen, and the function of helping smelting and secondary combustion of CO.