Abstract: The paper explores deeply on authorization in grid with respect to some key concept,including authorization parameters,authorization sequence and authorization model,then proposes in theory a framework for distributed authorization.Framework divides authorization into five parts.They are called in turn the trust management,policy management,privilege management,authorization mechanism & protocol management and authorization request management.Each part’s function is also prescribed.Not only this framework makes technology development for each part is more specific,but also clarifies the way of establishing concrete authorization mechanism.