Privilege　user　is　needed　to　manage　the　commercial　transactions,　but　a　super-administrator　may　have　monopolize　power　and　cause　serious　security　problem.　Relied　on　trusted　computing　technology,　a　privilege　separation　method　is　proposed　to　satisfy　the　security　management　requirement　for　information　systems.　It　authorizes　the　system　privilege　to　three　different　managers,　and　none　of　it　can　be　interfered　by　others.　Process　algebra　Communication　Sequential　Processes　is　used　to　model　the　three　powers　mechanism,　and　safety　effect　is　analyzed　and　compared.　©　2011　ICST　Institute　for　Computer　Science,　Social　Informatics　and　Telecommunications　Engineering.