Abstract: In the study of grid systems, the study of grid user（subject） management is relatively weak compared to that of the resource（object） management.Grid user expression, naming, the function and architecture of grid user management are very important for realizing an practical grid user management system.First the grid user management’s feature, scope and content are discussed, the expression and naming method of grid user are presented, and the whole life cycle state chart of grid user is described.Then a kind of architecture of grid user management is presented and a practical system—VegaGUS is realized.Finally the performance index and evaluation of this system are discussed.The system solves the key problems of the grid user management.