Aiming at the stepped frequency ISAR imagi ng problems of multiple moving targets in the same antenna beam overlapped over the range, a new method of stepped frequency ISAR imaging of multiple tar gets is proposed, based on the chirp Fourier transform (CFT). On the basis of the m u lti target echoes model of stepped frequency radar , the velocities of each target can be estimated accurately by the CFT. Then the multiple target ec ho signals can be separated by combining CFT and clean idea, thus the ISAR imag ing is finished. The simulation results also prove the validity of the proposed method.