Reverberation of active sonar that resemble clutter of airborne radar has space-time coupling characteristic. Based on which, a method of space-time ODN reverberation is presented in this paper. Project matrix method is utilized to design time and space ODN filters. The time ODN filter is used to suppress the mainlobe reverberation with the same direction as the target. The space ODN filter is used to the sidelobe reverberation with the same Doppler frequency as the target. Compared with other space-time adaptive processing approaches, this method involves smaller computation and makes real-time processing possible, while the system performance is close to optimal.