Present disclosure provide an audio signal encoding method and encoder, which relate to the communications field and can perform proper bit allocation for spectral coefficients of an audio signal. The method includes: splitting spectral coefficients of a current frame into subbands, acquiring quantized energy envelopes of the subbands; adjusting quantized energy envelopes values of some subbands; perform bit allocation according to adjusted quantized energy envelopes of the some subbands; quantizing a spectral coefficient of a subband to which at least one bit is allocated after the bit allocation.