A method and device for producing a crude copper. The method comprises: mixing and reacting copper smelting molten slag (1), a carbon-containing reductant (2) and an inert gas (3) under pressure, the pressure of the inert gas (3) being 100 kPa to 800 kPa. The device comprises: a furnace body (4) and gas nozzles (411) disposed on the furnace body (4), the gas nozzles (411) being located on the sidewall of the furnace body (4) and connected to the center of the molten pool.