Abstract: Laser Doppler measurement methods and coherent heterodyne detection were adopted to measure the frequency and amplitude of low frequency vibration. An experiment setup was built, based on which the Doppler effect was measured with a heterodyne laser interferometer and the standard frequency deviation was obtained. The results shows that the system can detect the object vibration at less than 500Hz frequency, and the measurement standard deviation is less than 5.610-8; The strength of the system detection signal is linear with the amplitude of object, demonstrating that the intensity detection amplitude reduces with the drop of the voltage of the piezoelectric ceramic. The result is helpful to know the characteristics of vibration targets.