Abstract: Information grid is a system using the grid technologies to achieve the sharing, and managing of information resources, and to provide information services. Based on the research work of the Vega-IG project, the key problems of the access control of the information grid are analyzed, a role-based access control model of the information grid is presented, and the versatile problem of the access control of the information grid is discussed. This role-based access control model is being implemented in the Vega-IG.