In this paper, a new algorithm based on sandglass transformation is presented for synthetic aperture radar (SAR)imaging of multiple ships.For cross-range signals of ship in the approximate form of linear frequency modulated (LFM) signals, theinstantaneous autocorrelation function of signals is used to implement the sandglass transformation and decouple the time and lagtime.Thus, cross-range signals can be integrated coherently and the multiple-ship image with high quality is achieved.In addition, adetailed analysis on the focusing characteristic of signal and the effect of cross-terms is presented, and a criterion of scaling factorselection for multiple-ship imaging is discussed.