A library book reservation method based on ultra high frequency RFID technology, including the following steps: step 1, using an RFID tag adhered on each book by using an RFID reading device, wherein the information read by the RFID reading device corresponding to each group of books includes ID information id of the tags, collecting the phase difference θ of the current tag, collecting the current time t of the current tag, and using Tag= to represent the read information of the RFID reading device corresponding to each group of books; step 2, sorting triples; and step 3, obtaining a phase change rule of the books, establishing a model, and analyzing the position relation between an RFID antenna and the books to sort the books.