In order to protect ERP system information from authorized users or non- trusted users, a trusted role based access control model was proposed. Combined with the characteristics of enterprises, trusted computation for user is designed to support roles assignment to the users. Meanwhile, Object Lifecycle States (OLSs) are presented for efficient access control to objects. Based on the value of trusted computation, users are assigned the corresponding roles to access control various resources. Finally, there is an empirical research on an ERP System implemented in a manufacturing enterprise.