Abstract: Based on the analysis of noise characteristics of the echo signal and principle of wavelet transform de-noising,the combination of threshold method based on 3σ criteria method and Module Maximum Value method is experimented,and with a variety of other classical de-noising algorithms combining in order to process comparative experiment.A new wavelet de-noising effect evaluation system that contains six indicators(noise ratio,smoothness,etc.) is proposed from multi-perspective and make a comprehensive and objective evaluation of the de-noising signal.Experimental results show that the combination of threshold based on 3σ criteria method and modulus maxima method can effectively remove the noise,the effect is better than other methods.