With the rapid development of the process of information of large-scale enterprises and organizations, information integration has become a hot research issue at present. Existing systems usually adopt access control model, such as ACL (access control list), MAC (mandatory access control) or RBAC (role-based access control), which results in the diversity of access control models in system integration. This paper designs a centralized authorization model supporting multiple access control, which authorizes permissions for multiple heterogeneous information systems on one point, and it makes permission management easier and more flexible in distributed environment. The process of decision-making is analyzed and methods of solving conflicts that results from decision-making are proposed at the same time. A concrete sample is cited so as to verify the feasibility of this model.