Based on a class of distributed delay systems, an adaptive sliding mode controller is proposed. According to the distributed delays, a suitable Lyapunov-Krasovskii functional is constructed, and the sufficient conditions of the asymptotical stability of the closed-loop systems are expressed in linear matrix inequalities. The adaptive sliding mode controller is constructed to satisfy the sliding mode reaching conditions. The delay-independent integral sliding mode is obtained and the sliding mode controller is simplified by the method. A numerical example is given to illustrate the validity of the proposed method.