A book placement posture identification method based on an RSSI signal value of RFID, including: step 1, horizontally moving to read the signal of an RFID tag placed in a book by using an RFID device; step 2, classifying triples with the same EPC number as a category to serve as the RSSI signal values of the internal RFID tag of the book obtained at different moments; step 3, preprocessing the data obtained in step 2; step 4, establishing a model to obtain a time-varying rule of the RSSI value of the RFID tag of the book; step 5, sampling data, training a classification model, and judging the placement posture of the book according to a model established according to test data and a classification model; and step 6, vertically moving to read the signal of the RFID tag placed in the book by using the RFID device.