When Synthetic Aperture Radar (SAR) works in the squinted mode in the case of a large grazing angle,the Range Walk changes greatly with the slant range.The traditional SPECAN imaging algorithm corrects the Range Walk only referring to the centered slant range,there are residual Range Walks on the range edge of the swath,which finally leads to target defocus.In order to solve this problem,a modified SPECAN imaging algorithm based on Chirp Scaling Principle is proposed.Firstly,it is multiplied by Chirp Scaling factor in the two-dimension time domain to eliminate the range variations of the Range Walk.Then,it employs the traditional SPECAN imaging algorithm to accomplish the two-dimension focus of the image.Numeric simulation results confirm the validity of the proposed algorithm.