Abstract: Circular Synthetic Aperture Radar(CSAR) is a new mode capable of long time observation. About processing moving targets,because of the circular trajectory, CSAR can obtain different radial velocity. By taking the advantages above , a new moving target (with constant speed ) real track calculating method is developed based on single channel CSAR. Firstly, we deduced the signal model of linear moving target with equal range and equal doppler. Then we measure the target apparent positions on a sequence of subaperture images . With the apparent positions and the signal model, the real track can be calculated. The proposed method is demonstrated on simulated moving targets data.