Machining method for rotor blade of gas turbine

The embodiment of the invention provides a machining method of a gas turbine rotor blade. The machining method comprises the following steps that the two ends of the rotor blade are smoothed; roughly and finely milling a tenon and a margin plate part of the rotor blade; roughly milling the blade profile of the rotor blade; and finely milling the blade profile of the rotor blade. A process route is optimized by integrating machining angles, the milling capacity of an extended blade root is improved by innovatively designing a forming cutter, and a milling program is optimized to eliminate a cutter connecting trace at the root extending position of a tenon, so that the quality of the milling surfaces of the tenon and a margin plate meets the requirements of a design drawing, and the machining efficiency is doubled; the size out-of-tolerance caused by secondary clamping can be eliminated through primary clamping, and the problems of surface quality of a triangular area caused by interference of a cutter and a cl