Abstract: The large range migration produced by missile diving acceleration flight make SAR image difficult. This paper establishes the echo model of the missile-borne SAR by using the high order range model based on the characters of the missile movements. Considering the large scene, the change of the slant range is analyzed in details. Then, the two-dimensional point target spectrum is derived by the method of series reversion. A large scene imaging algorithm used for diving acceleration flight is presented. Finally, simulation results are presented to demonstrate the accuracy and validity of the proposed algorithms. The resolution of range and azimuth are identical with the theoretical values.