This paper investigates the problem of tracking control for a class of linear networked control systems (NCSs). A linear system with interval time-varying delay is employed to describe the NCSs in consideration of both network-induced delay and packet dropout. An LMI-based sufficient condition on the existence of a network-based controller which guarantees an H ∞ tracking performance is derived by a new discretized Lyapnov functional. Based on the stability condition and the particle swarm optimization technique, an algorithm is presented to design the tracking controller. Two examples show the effectiveness of the proposed methods.