The utility model relates to the technical field of machining, in particular to a grinding and repairing tool for a rotor shaft neck, which comprises a grinding plate, an arc-shaped grinding surface matched with the radian of the rotor shaft neck is arranged on the grinding plate, and at least one groove used for being filled with grinding materials is arranged on the arc-shaped grinding surface.And an operation part is further arranged on the grinding plate. The utility model provides a grinding and repairing tool for a rotor shaft neck. When the grinding repair tool is used for grinding therotor shaft neck, the grinding repair tool is used; the grinding material filled in the groove can be in full contact with the arc-shaped surface of the shaft neck of the rotor; and the pressure of the grinding material in the groove on the rotor shaft neck is more stable, so that all parts of the rotor shaft neck are stressed more uniformly, the cylindricity of the ground and repaired shaft neckin the axial direction and the roundness precision of the rotor in the circumferential direction can be guaranteed, and the grinding and repairing effect on the rotor shaft neck is improved.