In this work, we illustrate a new decentralized optimization method for inventory control across large-scale supply-chains. The decentralized optimization method and the coordination algorithm provides a convenient approach to find the cooperative solution that is best for the whole supply-chain. Specifically, the scheme does not require each company to have explicit knowledge about the individual cost functions and the local constraints of the other companie. This factor helps eliminate the problems that result from informational deficiencies in large-scale supply-chains.