Abstract: For the target detection of millimeter wave radar the micro-Doppler effect induced by the micro-rotation parts of target spreads the spectrum of target echo, and the time-frequency coupling of the linear-frequency modulated signal extends the target in range, therefore the target is difficult to detect. In this paper, the features of target echoes are firstly investigated by modeling and simulation, then the complexity of measured data is analyzed. On the above basis of investigation, the edge-detection, mean-filter-centroid-detection, and close-operation-centroid-detection are presented and demonstrated using hte measured data.