The invention discloses a microwave protection method for a microwave metallurgical furnace. the microwave metallurgical furnace is provided with a shell; the inner wall and the bottom of the shell are each provided with a microwave protective layer; the bottom of the shell is provided with a supporting frame; an inner chamber of the shell is provided with a reaction bin; the outer side of the reaction bin is provided with a heat insulating layer; a microwave generator is arranged at the outer side of the heat insulating layer; the inner wall and the bottom of the reaction bin are each provided with a crucible layer; the sidewall of the reaction bin is provided with a plurality of magnetrons; the magnetrons separately penetrate through the crucible layers, the reaction bin and the heat insulating layer; one end of each magnetron is connected with the microwave generator; the other end of each magnetron extends into the reaction bin; a material retaining screen is arranged at the innerchamber of the reaction bin and is fixedly connected with the microwave generator; a discharging passage is arranged at the bottom of the reaction bin; and a control valve is arranged on the discharging passage. The microwave protective layers are arranged for preventing microwave from acting outside the device so as not to cause harms to a worker, and meanwhile the microwave protective layers canplay a protection effect on the reaction bin as well.