A stereo signal encoding method includes determining a window length of an attenuation window based on an inter-channel time difference, determining a modified linear prediction analysis window based on the window length of the attenuation window, where values of at least some points from a point (L−sub_window_len) to a point (L−1) in the modified linear prediction analysis window are less than values of corresponding points from a point (L−sub_window_len) to a point (L−1) in an initial linear prediction analysis window, and the window length of the modified linear prediction analysis window is equal to a window length of the initial linear prediction analysis window, and performing linear prediction analysis on a to-be-processed sound channel signal based on the modified linear prediction analysis window.