The invention relates to a narrow-band interference suppression method and a narrow-band interference suppression device. The device comprises an adaptive filter module, a fast Fourier transformation module, a narrow-band interference suppression module and a fast inverse Fourier transformation module. The method comprises the following steps of: 1) forecasting a dispersion sequence obtained through sampling to obtain a narrow-band interference forecast signal according to an adaptive algorithm; 2) multiplying the narrow-band interference forecast signal by a factor K to obtain a forecast factor signal, and subtracting the forecast factor signal from a received signal to obtain a first signal; 3) transforming the first signal to a frequency domain, and performing frequency domain wave trapping processing on the first signal in the frequency domain; and 4) converting the first signal subjected to frequency domain wave trapping into a second signal in a time domain, and inputting the second signal into a spread spectrum signal demodulator to finish narrow-band interference suppression. By the method, the shortcoming that a time domain adaptive filter cannot completely suppress the interference is overcome; and energy leakage in a frequency domain wave trapper is reduced.