Aiming at improving multiple tags reading efficiency in RFID, it analyses the binary search anti-collision algorithm, and puts forward an improved binary tree half search algorithm. By constructing a Huffman tree, using a custom code, using the stack operation to determine the collision bit, with a half search method to reduce duplication of path, ultimately determines the shortest path length. Data analysis and experimental results show that, the binary tree half search anti-collision algorithm can significantly reduce the search depth, and improve the work efficiency of RFID tag reading.