A method for quantizing vector. The method includes: performing a quantization process on a vector to be quantized by use of N basic codebook vectors and the adjustment vectors of each of the basic codebook vectors, generating a basic codebook vector and an adjustment vector used for quantizing the vectors to be quantized, N being a positive integer larger than or equal to 1. According to the present invention, based on the method a device for quantizing vector is disclosed. According to embodiments of the present invention, the quantization of an input vector is done by introducing the modification vectors for the base codebook vectors, therefore the memory amount of the base codebook vectors is reduced effectively, and the calculation amount is merely the calculation amount required for going through N codebooks. Therefore, the complexity of the vector quantization could be decreased effectively.