Based on the synthetic aperture radar (SAR) geometric model, a novel method of jamming space-borne SAR by utilizing the array beam-pattern characteristics of frequency diverse array (FDA) is proposed. A small frequency increment, as compared to the carrier frequency, is applied between the FDA elements to produce multiple false targets in the final space-borne SAR imaging. The separations between the false targets are determined by the frequency offset. Based on the imaging geometry in side-looking mode, this paper derives a range-Doppler (RD) algorithm for the space-borne SAR imaging under FDA jamming signals. Simulation results demonstrate the effectiveness of the proposed approach.