Abstract: For precise position control of solenoid valves with strong non-linear characteristics it is essential to respond to load fluctuations including non-linear terms. We study the method of estimating the state of disturbance by considering load variation and non-linear term as disturbance and the method of applying it to controller. By constructing the Luenberger’s observer with the disturbance state, the state of the observer is included in the control input to perform feedback linearization and the PI controller can be configured to achieve precise position control and this system obtains the robustness to adapt to the load variation. As a result, the robustness of maintaining the target position by the adaptation of the constant load of 5 [N] with the position error of the steady state within 0.1% was obtained.