An anti-theft method to be executed in an active peer, comprising: (a) transmitting radio RF signals to a passive peer to detect whether one of the active peer and the passive peer as a monitored object is in the coverage area of the radio range of the other one of the active peer and the passive peer as a dock; (b) checking whether the monitored object is permitted to leave the dock when detecting that the monitored object is going to leave the area of the dock; (c) sending an alarm signal to an alarm apparatus if the monitored object is not permitted to leave the dock.