The Gateway Server Authorization System(GSAS) presented in this thesis is a database authorization system. GSAS is responsible for user`s authorization, and privilege management, audit service. Only users that are filtered in GSAS can access the DBMS(Data Base Management System) through middleware. GSAS is located at the DBMS and already contains an authorization record for user accessing a specific DBMS. GSAS on consists of several components, namely an authorization manager, a privilege manager, and an audit manager. As an authorization manager and a privilege manager can only approve a pass at the same time, a user can get accessibility for DBMS.