A novel interferometer,which directs to measure and pick up micro-vibration signal free of distortion,is proposed. The system is based on Michelson interferometer. It uses a fiber laser with narrow linewidth as light source,and adopts homodyne demodulation with phase generated carrier scheme to restore signal. The frequency response range is effectively widened through optimizing the driving circuit of PZT,which is used as phase modulator. And the signal to noise ratio(SNR)is increased with a phase shifter introduced. The system has a good linearity in the frequency range from 50 Hz to 4 kHz. The SNR and harmonic suppression ratio of output signal is 60 dB and 50 dB respectively. The sensitivity of the system is 1×10^－5rad/Hz^1/2.