The invention discloses a clean pyrolyzing furnace comprising an upper furnace body and a lower furnace body. A pyrolyzing chamber is arranged in the upper furnace body. A pyrolyzing pipeline arrangedin the horizontal direction is arranged in the pyrolyzing chamber. A separation chamber is arranged at the discharge end of the pyrolyzing pipeline. A combustible gas channel connecting the separation chamber with the pyrolyzing chamber is formed in the upper furnace body. The top of the lower furnace body is provided with a hot smoke channel communicating with the bottom of the pyrolyzing chamber. The lower furnace body is provided with a combustion chamber and a feed pipe for feeding to the edge of the combustion chamber. A dry mud feeder is arranged outside the lower furnace body. The lower end of the separation chamber is provided with a dry mud discharge outlet for feeding to the dry mud feeder. A vertically arranged rotary shaft is arranged at the bottom of the combustion chamber and is provided with a plurality of stirring arms which drive materials to move to the bottom center of the combustion chamber. The bottom of the combustion chamber is provided with an ash outlet closeto the rotary shaft. Through the clean pyrolyzing furnace provided by the invention, combustion ability and effect are improved effectively, and energy is saved.