In this paper, a new switching based multiple models adaptive controller is proposed for a class of discrete time systems with large uncertainty and abrupt change of system parameters. Firstly, the parameters space of systems is divided into several convex subspaces, and multiple adaptive models are established in each space. In order to overcome multiple models degradation and maintain diversity of the model to cope with the parameters abrupt change, constrained second level adaptation is used to real-time estimate the unknown parameters, and sub-controller is designed. Then, based on the switching strategy, the optimal sub-controller is selected as the controller of the system, so as to reduce the system transient error and improve the dynamic performance of the system. Finally, the numerical simulation is carried out. The results show that, the controller combines the advantages of the switching mechanism and second level adaptation, which can rapidly approach the new operating point of the system after the parameter jump, significantly shorten the transition process of the system, and improve transient performance.