The invention discloses a variable pitch screw rotor forming device. The variable pitch screw rotor forming device comprises a machine shell, a screw forming die arranged in the machine shell and provided with a screw cavity, a push rod used for pressurizing metal powder in the cavity, and a guiding sleeve used for guiding the push rod. According to the forming device, it can be guaranteed that a screw rotor has good precision, later precision machining is convenient, meanwhile, high machining efficiency is achieved, and batched production of the screw rotor is convenient to achieve.