Abstract: In this paper, the radar echo of flexible target is analyzed, and an empirical mode decomposition (EMD) based motion compensation method is proposed. The method firstly estimates the Doppler induced by the bulk motion via extracting the trend of instantaneous frequency. Based on the result, bulk motion compensation and micro-Doppler extraction are realized. Owing to the adaptive characteristic of EMD, the method could be realized without prior information about the motion of target. The experiment results based on simulation and measured data show that the method can compensate the bulk motion and extract micro-Doppler signal for flexible target.