Abstract: According to the requirement of automatic sensing user's identity for ambient intelligence,a blue-tooth-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.