Abstract: In this paper, the design problem related to the decentralized loop transfer recovery for large-scale interconnected systems is discussed. It develops a new method which makes interconnections between subsystems be "block-diag" by using matrix singular value decomposition technique. The LTR of centralized multivariable control systems is then generalized to decentralized control large-scale interconnected systems by H∞ optimal theory. The difficulty to compute the infimum of H∞-norms of recovery matrices in the set of all possible gains of decentralized observers is avoided.