The analysis of the relative importance of components of MFCC for both speech recognition and speaker recognition using DTW recognizer in various noise environments are given.For English digit and under the Euclidean distance definition,the experiment results show cepstral components from C 2 to C 16 contain the most useful speaker information,while C 0 and C 1 are usually harm to speaker recognition.Cepstral terms from C 1 to C 12 are found to contain the most useful speech information.In both tasks,the additive noise decreases the relative importance of low MFCC terms faster than that of the middle and high MFCC terms,and the decrement depends on the speech SNR.The channel distortion will deteriorate low terms more than the middle and high MFCC terms in both tasks,also.