A decentralized model predictive control scheme is proposed for complex interconnected systems by using extended state observer (ESO) to deal with the coupling between subsystems and disturbance. Firstly, the considered system is decomposed into several lower-order subsystems with the local model predictive controller. In order to improve the stability and disturbance rejection performance, the ESO is introduced into the local model predictive controller. The coupling and interference of the subsystem are estimated by the proposed ESO and compensated by using a feedforward compensation strategy. Finally, a liquid level control system is given to demonstrate the effectiveness of the proposed method.