Abstract: High accuracy estimation of DOA(Direction of Arrival) in low SNR (Signal-Noise-Ratio) is a intractable problem in signal processing. Traditional methods of DOA estimation and modern space spectrum estimation algorithms can be only effectively used in high SNR. In this paper, classical amplitude-method of DOA estimation, digital multi-beams forming and FFT are integrated, and a amplitude-algorithm of DOA estimation by processing in frequency domain is put forward. Simulation results show that the algorithm can estimate DOA effectively when SNR is 0~-25 dB.