In a multi-domains application environment, where distributed multiple organizations interoperate with each other, the local access control policies should correspondingly be integrated in order to allow users of one organization to interact with other domains. One of the key challenges of integrating policies is conflict detection and resolution while preserving policy consistency. This paper addresses several types of potential conflicts and consistency properties with a systematic and rigorous approach. In the approach, graph theory, network flow technology and colored Petri nets are applied for specifying and verifying a secure interoperation design. The component-based integration of policies is applicable for both static and dynamic multi-domains environments.