The precise target identification is significant for commanding decisions and enemy identification. The micro-Doppler effect (MDE) can reflect the subtle movement characteristics of the target, which provides a new way for the target detection and recognition. However, the current research is mainly on the micro-motion feature extraction and classification of the targets, which is not capable for identifying the targets of the same type. This also reduced the application of the MDE. In fact, by accurately estimating the micro-motion parameters and combining sufficient prior knowledge, the target can be accurately identified. Further, the MDE detected by laser in infrared band has higher sensitivity and resolution than microwave detection, especially for the MDE generated by weak vibrations. Thus, in this paper, the photocurrent model of the laser detected MDE echo signal is established. The all-fiber coherent laser detection system for target micro-motion is designed. The detection sensitivity of and resolution requirements of the multicomponent micro-Doppler features are analyzed. Based on the time varying auto-regression (TVAR) model, the precise parameter estimation method for micro-motions are proposed, which provides the basis for target identification. The validity of the theoretical analysis and estimation method is verified through simulation. This research is helpful for extending the application of MDE from classification to precise identification in the future.