Abstract: In order to improve the robust performance of whispered speaker indentification,a kind of whispered speech parameter called instantaneous frequency estimation (IFE) is proposed based on the AM-FM representation of speech signal.According to the formant modulation theory of speech production,the instantaneous envelope and frequency of speech are extracted by multiband demodulation analysis (MDA).IFE is then obtained by the weighted estimation both on envelope amplitude and frequency to represent the accurate frequency structure of speech.The proposed speech parameters have been applied for whispered speaker indentification and compared with conventional MFCC.The experiment results show that,as the test objectives increase,the IFE parameters perform as well as MFCC,even a little better.When the test channels are changed,comparing with MFCC,IFE effectively improves the robust performance of system.