The NORGREN micro-proportional valve servo control method can also take the form of: The direct current directly added to the reluctance type rodless proportional solenoid valve two electromagnetic coils, and then through the three tube base and the potentiometer connected to both ends, and through the sliding contact of the potentiometer, so that the control current in two, return to the power supply, and the working voltage between the two electromagnetic coils form a proportional change relationship, And in the non-magnetic material double rod piston type hollow valve body inside the sliding cylindrical valve core, in the adjustment and balance of two strengths of different magnetic field forces, complete the oil circuit switching and flow control operation. The servo control method of the reluctance type rodless proportional solenoid valve can also be simplified in this way, that is, the direct current is directly added to the sliding contact of the potentiometer, and after the "shunt" of the potentiometer, it is respectively supplied to two electromagnetic coils for work. This method is not recommended because it is easy to generate sparks on the moving contact. However, it still falls within the scope of the present invention.