Electric power towers monitoring is of great significance to ensure transmission lines operate safely. A tilt sensor based on fiber Bragg grating（ FBG） for electric power tower monitoring is researched

heavy weights are fasten on the free end of equal strength cantilever beam

of which the bottom is fixed on the sensor shell

two FBGs are pasted on the center symmetrical lines on both sides of equal strength cantilever beam

heavy weights generates deflection on the free end of the equal strength cantilever beam when the electric power tower is slanting

leading to shift of center wavelengths FBG angle of the electric power tower can be measured by monitoring center wavelengths of FBG in the sensor. Experiment indicates that the repea

tability error is 1 % FS

the nonlinear error is 0. 4 % FS

the hysteresis error is 0. 8 % FS

when the tilt angle is less than 15°. The repeatability error is 1. 5% FS

the nonlinear error is 0. 77 % FS

the hysteresis error is 1. 1 % FS

when the tilt angle range of 15°

45°.