A novel method based on summation and difference sequence of ranges is proposed in order to extract micro-motion signatures of targets with complex motions which are composed of translation and vibration.The method estimates summation and difference of ranges from one dimensional range profile and obtains summation and difference sequence of ranges from time-range profiles of targets.Vibration amplitudes and vibration periods of different scatterers are achieved and translation ranges of targets are exactly acquired from summation and difference sequence.The restrictive conditions of the method were analyzed and simulation experiments were carried out.Simulation results validate the theoretical analysis and the signature extraction method.The method discussed in the paper can be extended to analyze other targets with general translation and other periodic motions.