A system of detecting micro-Doppler effect based on laser coherent radar worked in the 1550 nm wavelength is presented,and experimental research on micro-Doppler effect of detecting the dynamic target is developed. The time domain signal of the returns is decomposed into a set of components that are represented by different wavelet scales. The micro-Doppler features are extracted by sorting the components that are associated with the vibrational/rotational motions of a target and reconstructed by inverse wavelet transform. After the extraction of micro-Doppler features,time-frequency analysis is employed to analyze the oscillation and to estimate the motion parameters. The analysis of experiment results show that micro-Doppler information of the dynamic target can be detected effectively by this system,and tiny vibration can be acquired effectively by analysis of multi-resolution analysis and time-frequency analysis of short-time.