Abstract: HHT is a new and self-adaptable method for time-frequency analysis.The theory of HHT is studied and a speech enhancement method based on HHT and human auditory masking is brought forward.First the signal is decomposed into IMFs with the method of EMD,then the high-frequency IMFs is processed with the human auditory masking,finally the signal is reconstructed by adding the treated IMFs with the residual IMFs.Simulation experiments show that it can reduce the measured value of speech distortion and improve the SNR,speech articulation and intelligibility.The results display the superiority of this method over the human auditory masking and the spectral subtraction method.