Disclosed are a multi-channel audio signal encoding method and apparatus. Audio signals of P channels in a current frame of a multi-channel audio signal can be obtained, where the audio signals of the P channels include audio signals of K channel pairs; respective bit quantities of the K channel pairs are determined based on the respective energy/amplitudes of the audio signals of the P channels and a quantity of available bits; and the audio signals of the P channels are encoded based on the respective bit quantities of the K channel pairs to obtain an encoded bitstream, to improve encoding quality.