Abstract: Synthetic aperture radar is an important remote sensing means.Since it's impossible for airplane to fly along a straight line with the same velocity,highly accurate motion compensation for airborne platform is necessary.The motion error of airborne platform could be measured by motion sensors,and it consists of ground speed error and LOS(line of sight) error.This paper analyzes the raw data of synthetic aperture radar in which there exists movement error,and proposes an algorithm to offset the movement error.Test with simulated data proves the concept is valid and feasible.