Abstract: In order to improve the quantization quality of the excitation gains in ACELP speech coder, we present a general method for establishing the gains codebook in widely used ACELP speech coders. This method can be applied to ACELP speech coder at any bit rate. Experimental results show that the performance of 6 bits gains vector codebook, which is established by the purposed method, is equal to that of 8 bits gains scalar codebook.