Abstract: When radar seeker detects moving target on the sea, the sum and difference beams space-time adaptive processing (ΣΔ-STAP) algorithm has a very limited ability to suppressing sea clutter due to the serious spreading of sea clutter spectrum, an efficient ΣΔ-STAP algorithm based on low-rank matrix recovery is proposed. The proposed algorithm models the ΣΔ-STAP signal based on low-rank matrix recovery theory, ΣΔ-STAP algorithm is firstly used for preprocessing the sea clutter, then the robust principal component analysis (RPCA) technique is used to separate the sparse matrix of target component from the range-Doppler data matrix, finally the moving target is effectively detected from the rang-Doppler spectrum map. Simulation results demonstrate the effectiveness and robustness of the proposed algorithm in the low SNR conditions.