This paper presents two well-known designs of model reference adaptive control (MRAC) based on state and output feedback, to control microelectromechanical system AC voltage reference source (MEMS AC VRS). The best performance of AC voltage reference is achieved when the movable plate of MEMS capacitor is located and stayed under the pull-in point. This study proposes two MRAC schemes to place the movable plate near the pull-in point in the presence of parameter uncertainties. Moreover, the asymptotic stability of the closed-loop system is guaranteed by the Lyapunov theory and Barbalat’s Lemma. Finally, simulation results verify the effectiveness of theoretical methods.