Abstract Phase Gradient Algorithm (PGA) is accomodated to focus the StripMap SAR data in this article. A new approach to StripMap SAR autofocus, StripMap PGA(SPGA), is developed based on the difference between the received signal of StripMap SAR and SpotLight SAR and the classic PGA is referenced. The focused SAR images from SPGAdoes not have the problem of the shift between the blocks which can be found in the images from the traditional StripMap autofocus method. SPGA can get well focused SAR images from more universal scene because of the employment of phase error surface.