Department of Defense (DoD) of USA has proposed new architecture framework (DoDAF v1.5) recently to guide the development of new military systems. Net-Centric Environment (NCE) and Service Oriented Architecture are highlighted in it. In order to ensure the security of the future military systems, a service oriented decentralized access control (SODAC) model is proposed. Detailed construction and formal definition are given. With the model, authentication will be processed at the entity end to implement decentralized control. At last, related issues, analysis and implementation of the model are discussed.