The utility model provides a multi-step molding reamer, which comprises a cutter body and a cutter head, wherein the cutter head is formed at one end of the cutter body; a first cutting edge is formed at the end part of the cutter head; a plurality of reaming parts are also formed on the cutter head; in the adjacent reaming parts, the diameters of the reaming parts which are far away from the first cutting edge are more than those of the reaming parts which are close to the first cutting edges; the cutter head is also provided with a chip space; the chip space extends from one end to the other end of the cutter head; a second cutting edge of the cutter head is formed on the edge of the chip space; the second cutting edge is formed on the side surface of the cutter head; the taper of the core-thickness positive cone of the cutter head is 0.65: 10 or 1.0: 10; the wall surface, which is in contact with the hole wall of a stepped hole which is formed by processing, of the cutter head forms a molding surface of the cutter head. By using the multi-step molding reamer provided by the utility model, the requirements that a material for processing a hole of a hydraulic valve body is difficult to process, has multiple steps and is high in service life are met. By using the multi-step molding reamer, bits which are of multiple structures are combined with the corresponding molding surfaces, the corresponding stepped holes in a molding place can be processed at one time; the processing efficiency and the processing precision are high.