Abstract: This paper proposes the use of complex wavelet transform to extract the envelope of borehole echo signal, and the image detection test is carried out by using the echo signal processing method of borehole wall based on complex wavelet transform. Experimental results show that the extraction of borehole echo envelope and the signal processing method based on complex wavelet transform can effectively improve the signal to noise ratio of detection system, enhance image contrast, and display better borehole image.