Abstract: A detection method for ocean surface currents based on the Doppler shift and Bragg scattering for sea clutter imaging using X-band marine radar is addressed in this research. A preprocessing algorithm for current inversion combined with geometric filtering model is presented. Maximun current velocity is not required for band-pass filter processing，since accurate current velocity can be obtained only with liner wave theory dispersion equation and a least-squares algorithm. As compared with the conventional flow detection method using X-band navigation radar，this new algorithm is simple and efficient.It uses resources effectively,and can be applied to both shore-based X-band and shipborne X-band navigation radar. A validation comparison with sea surface current data from a near-by HFUWR shows that this algorithm effectively improves the accuracy and stability of the radar.