The robust H_∞ control of a class of uncertain networked control systems with network-induced delay and data packet dropout is studied. A new Lyapunov-Krasovskii functional is proposed, and sufficient conditions for guaranteeing the robust stability and H_∞ performance of the considered system are derived based on an improved version of Wirtinger inequality. The derived conditions can lead to less conservative results than existing corresponding ones. A cone complementary linearisation(CCL) algorithm is given to solve the suboptimal robust H_∞ controller gain. Numerical examples are given to illustrate the effectiveness of the proposed methods.