Transmission line faults caused by wind deviation account for a large proportion in power grid operation. In order to monitor the change of the yaw angle of the insulated suspension insulators in real time, the fiberoptic sensing technology is applied by studying the load model of the overhang insulator wind bias. The online detection system for the wind deflector of the suspended insulator was built, and the online monitoring of the skew angle of the 110 kV pole suspension insulator in the Zhaotong area of Yunnan Power Grid was realized. According to the monitoring data, the change of the yaw angle of the suspended insulator string is consistent with the trend of the theoretical calculation model, and the variation range is roughly between -4° and +4°. The results show that the online detection method of windsounding angle of optical fiber sensing is accurate and reliable in practical application, which provides a certain reference for the safe operation of transmission lines.