The vibration signals of transformer core are measured using optical fiber Fabry-Perot（F-P）vibration sensor with vibration test system.Optical fiber F-P sensors are pasted in the transformer core

and the vibration signals of core transformer are directly distilled

the error of indirect measurement is avoided.Measurement principle of the optical fiber F-P is analyzed

and the mathematical model of the F-P gap is built up.The experiments validate that at the no-load conditions magnetostrictive rate of core is linear to square of no-load input voltage.