Abstract: A new fast codebook designing algorithm referred to as FCLECA (fast competitive learning and error correction algorithm) and based on a modified CPN(counterpropagation network) is presented. The corresponding fast vector quantizer model based on the modified CPN is illustrated. Details of the critical steps and parameters in FCLECA and its time complexity are discussed. Results of simulating experiments indicate that with the new algorithm the training time in codebook designing is greatly reduced, while quality of the generated codebooks is improved. The new algorithm is effective and feasible in vector quantization.