Abstract: The design problem of robust H_∞ controller for networked control system(NCS) with time-varying sampling period is studied.Based on the varying sampling period,a switching method,of which the sampling period switches in a finite set,is proposed to model the NCS with time-varying sampling period,long-time delay and packet dropout as a switched system.With the proposed switching method,a non-convex feasibility problem is formulated into a multi-objective optimization problem subject to LMI(linear matrix equality) constraints,and an H_∞ controller design method for NCS is presented.The simulation results illustrate that the proposed H_∞ controller design method for NCS with sampling period switching is effective.