Abstract: Arc array synthetic aperture radar (SAR) is a novel array imaging system for wide-area observation. It has a wide range of observations and high resolution. Due to the characteristics of azimuth sampling at equal angular intervals, it is difficult to derive the two-dimension spectrum of the target echo signal, and existing imaging algorithms of linear array are no longer applicable. As for above issues, a new arc array SAR imaging processing method based on high-order approximation of slant range is presented. The method performs high-order approximation for the range model, obtains the two-dimensional spectrum of the target echo signal through series reversion, and then compensates the range migration and the coupling of distance and azimuth in the two-dimensional frequency domain. Finally, obtains the focused image. Simulation analysis of the point targets validates the effectiveness of the imaging approach.