According　to　the　requirement　of　automatic　sensing　user＇s　identity　for　ambient　intelligence,　a　bluetooth-based　identity　sensor-net,　which　combines　advantages　of　bluetooth　ad　hoc　network　with　ethernet　is　proposed.　A　bluetooth　badge　of　user＇s　identification　is　introduced　in　detail,　so　as　to　build　an　authentication　system　without　any　user＇s　cooperation.　It　is　demonstrated　by　experiment　that　the　bluetooth-based　identity　sensor-net　can　automatically　sense　the　user＇s　identity,　and　has　the　advantage　of　robustness.　And　it　has　provided　the　basis　to　build　an　ambient　intelligence　system.