The decentralized H∞ control problem for discretetime large-scale overlapping systems is considered in this paper. Based on the founded stability theorem of discrete-time systems, a sufficient condition for the existence of a decentralized H∞ twoparts-controller for discrete-time large-scale overlapping systems is presented in terms of the solvability to a certain discomposed system of matrix inequalities, by the Cone Complementary Linearization (CCL) algorithm. And the method can be extended to systems with uncertainties.