The model of micro-motion targets of Symmetrical Triangular LFMCW (STLFMCW) radar is provided. Based on the micro-motion model, the characteristics of the echoed signal are analyzed and the form of the micro-Doppler signal is obtained. The phenomenon that the micro-motion target's continuous moving during the scan period will induce the widening and deviation of micro-Doppler curves is discussed. To solve this problem, a method for removing the widening and deviation of the micro-Doppler curves is proposed. The echo phases can be compensated by using this method. Then, the parameters of micro-motion target are extracted by the extended Hough transform. The simulation experiment validates the effectiveness of the proposed method.