Abstract: To solve the shortcomings of the AISG protocol, an antenna line device (ALD) scanning algorithm based on binary scanning tree is proposed. In leaf scanning phase for existing ALDs, leaf nodes are scanned directly with scanning codes corresponding to the identified nodes from the previous scanning, while in root scanning phase for new arriving ALDs, we start scanning from the root node. By utilization of an adaptive collision avoidance mechanism and the leaf-root scanning method, the collision frequency during ALD scanning is effectively reduced. The results of simulation show that the proposed algorithm can effectively shorten the ALD scanning time and increase the efficiency of ALD search.