The invention discloses a reduction oxidation furnace for refining phosphorus by a hot method, which comprises a furnace body and a blow gun, wherein the furnace body is provided with a slag outlet, a smoke outlet and a fusant inlet for adding molten phosphorus into the furnace; and one end of the blow gun is inserted in the furnace body. According to the reduction oxidation furnace for refining phosphorus by a hot method, impurities in flue gas containing phosphorus pentoxide are reduced, and the phosphorus pentoxide with high purity can be simply extracted at low cost.