n the library, recognizing the behaviors of readers can better excavate the reading habit of the readers and bring convenience to the book management. We present the design and implementation of a reading activity recognition approach utilizing passive RFID tags. By collecting and analyzing phase value distribution feature, our approach can recognize which book has been picked up. We give a detailed analysis of factors that can affect phase value in theory and combine these factors with relevant activities. And then we infer the activities in real time through monitoring the phase of tags. Besides, we implement our approach with off-the-shelf RFID equipment.