An audio signal encoding method and apparatus, and an audio signal decoding method and apparatus are provided. The audio signal encoding method includes: obtaining a frequency-domain coefficient of a current frame and a frequency-domain coefficient of a reference signal of the current frame; performing filtering processing on the frequency-domain coefficient of the current frame to obtain a filtering parameter; determining a target frequency-domain coefficient of the current frame based on the filtering parameter; performing filtering processing on the frequency-domain coefficient of the reference signal and a reference frequency-domain coefficient based on the filtering parameter to obtain a target frequency-domain coefficient of the reference signal; and encoding the target frequency-domain coefficient of the current frame based on the target frequency-domain coefficient of the current frame, the target frequency-domain coefficient of the reference signal, a reference target frequency-domain coefficient. The method can improve audio signal encoding/decoding efficiency.