A self-mixing laser vibrometer system based on vertical cavity surface emitting laser（VCSEL）is proposed.The short-time Fourier transform is employed to analysis the Doppler signal.While remove singularities by taking advantage of wavelet transformation to obtain accurate Doppler frequency.The direction of motion is determined by technique of triangle-wave current modulation.The error of displacement is within 1% and is realized the precision measurement of the vibration object displacement.