This paper proposes the method of a Hopfield-type neural network (HNN) for extracting Doppler spectrum from ocean echo. First, it introduces the basic principle of HNN for optimized processing. Second, expanding the principle of utilizing autoregression (AR) to estimate frequency spectrum, we point out how to apply HNN in spectrum estimation. Last, the three methods are utilized to process actual data, that is, the conventional fast Fourier transform method, modern spectrum estimation--AR method, and the spectrum estimation method based on HNN. The results obtained by the three methods prove that the spectrum estimation method based on HNN is feasible for extracting the Doppler spectrum from ocean echo.