According　to　the　requirement　of　natural　human-computer　interaction　for　Ambient　Intelligence　(AmI),　a　Bluetooth-based　authentication　technique　is　provided.　An　authentication　network　combining　advantages　of　Bluetooth　ad　hoc　network　with　the　Ethernet　is　introduced　first　in　detail.　Then　we　propose　a　Bluetooth　badge　for　storing　the　user＇s　identification　information.　Finally,　the　authentication　system　based　on　Bluetooth　badge　and　authentication　network　is　introduced.　It　is　demonstrated　experimentally　that　the　Bluetooth-based　authentication　technique　can　authenticate　the　user　automatically.