Abstract:To compensate for the deficiencies of traditional threshold functions and obtain the heart sound with high SNR for better analysis，a novel threshold function was proposed in this study. The function quantified the detail coefficients of each level of noisy heart sounds effectively through adjusting the values of the parameters a and m. In the simulation, the traditional soft and hard threshold functions and the new threshold function were used in noise reduction for many cases of standard heart sounds respectively and the comparative analysis of the effect of noise reduction was made. The new threshold function was applied to noise reduction of the measured heart sounds as well. The results indicated that the new threshold function could better reserve the characteristics of heart sounds, eliminate noise effectively, and was of strong practical value.