The uncertainty and time variation of the refresh time interval exist in non-uniform sampling systems, which cause great difficulties to design the system controller. To deal with the problems, the refresh time interval is regarded as the time delay variable, and the system dynamic changes in different time delays are characterized by different subsystems. The changing laws of time delay are transformed into the switching laws among different sub models.The non-uniform sampling system is described as a class of discrete-time switched systems with some subsystems. Sufficient conditions of the robust stability of the closed-loop systems with the uncertain refresh time interval are given in the form of theorems.