Provided are an electronic expansion valve, a control system, and a control method, including: a step motor and a Hall sensor; the step motor includes a rotor and a stator; the rotor includes a permanent magnet; the Hall sensor is provided on the outer periphery of the permanent magnet; the Hall sensor and rotor are arranged in the radial direction, and the stator and Hall sensor are arranged in the axial direction; the main-body part of the Hall sensor is used for sensing the magnetic pole change of said permanent magnet; such a structure reduces the effect that an operating environment has on the Hall sensor when detecting a signal.