Aiming at improving the existing problem of over detection and missing detection in traditional way, The article proposed the detection system for loosening of bolts of wind power tower based on internet of things technology. In this system, the pressure information of the hydraulic pump used to avoid obtaining false results, and the RFID reader of the sensing layer sensor in the Internet of things is used to design the target identification detecting circuit in the system. Because the installation of RFID tag needs reform existing equipment, the paper analyses the force conditions of the modified wind tower bolts by using ANSYS software, and provides a safe modification scheme. The alarm circuit of over detection and missing detection is designed to assist in detecting the looseness of the bolts. The mass-storage circuit is also designed to save detection results in the SD card, which is convenient to read and analyse detection results. The Effect of practical application shows that using this system can eliminate missing detection, reduce over detection, and improve the efficiency of bolt loosening detection.