The transmission conductor and charged structure at the bottom of insulator string tend to be close to the transmission tower due to the effect of wind deviation. The discharge and tripout may occur once the distance between them is less than the minimum air gap value. Therefore, the wind deviation of insulator string threaten the safe operation of power grid seriously and may lead to an enormous economic loss. Under the circumstance, this paper designs and develops a fiber Bragg grating (FBG) tilt sensor. In this sensor, the gravity hammer is fastened on the free end of equal strength cantilever beam which have one FGB pasted on the central symmetrical lines of both sides. The developed inclination sensor is packaged and then installed on the top of the insulator string together with the fiber Bragg grating load cell by the pattern of hoop clamp combination. The insulator string on 30# Tower of an 110 kV transmission line in the Yunnan Power Grid is monitored by the installed device. By combinatory analyzing the monitoring data and wind data, the variation characteristics of windage angle with wind speed are obtained. The nonelectric measuring of fiber Bragg grating tilt sensor provides a reference for safe operation of power transmission line.