Multiple model adaptive control (MMAC) of discrete time plant is considered in this paper. The plant can be a time invariant system with unknown parameters or a time variant system with jumping parameter. Localization method is combined with the design of discrete time system MMAC. Multiple models of the plant are set up to cover the uncertainties of the plant dynamics. Every sample time, by using localization method, only a few of models which are closer to the “true” model of the plant are selected to form a multiple model controller, so the big computation burden of the multiple model algorithm is greatly reduced. It is proved that the closed loop system is stable when multi-model controller is used to a linear time-invariant plant with unknown parameters. The simulation results are given to show the usefulness of the proposed method.