A new kind of coupling high-frequency fiber-optic vibration sensor and its corresponding demodulation circuit and signal process system were presented. The waveform and frequency of high-frequency vibration signals were tested, and the responses of fiber-optic sensor to different drive voltages and different directions were discussed. The influences of transmission medium shape and qualiy on the results were investigated. The experimental results show that the cutoff frequency of the coupling fiber-optic vibration sensor is 8 kHz; its amplitude measuring sensitivity is 325 mV/mm; and its frequency and amplitude response error is less than 1%.