Based on Pseudo random noise codes of Chinese COMPASS Navigation Satellite System (CNSS), opened access at the end of 2012, space-surface bistatic synthetic aperture radar (SS-BSAR) passive imaging system is investigated. Furthermore, a modified Range Doppler (RD) algorithm that takes direct signal as reference signal in range compression is proposed. The good imaging performance of SS-BSAR system is demonstrated via modified RD algorithm simulation results.