Considering the problem of noise reduction of acoustic emission signals in the cross-correlation location of through-hole leakage sources in pressure pipelines, the selection of the optimal wavelet base for reconstructing the leakage signal with wavelet coefficient is carried out. First, the acoustic characteristics of the leakage signal of the pipeline through-hole was analyzed; Then, the occurrence time of the leakage acoustic emission event was analyzed by short-time Fourier transform, which was utilized to obtain the basic time-domain waveform in this time period, and the appropriate wavelet base was selected compared with the similarity between the basic time domain waveform and the standard wavelet base；Further, the optimal wavelet basis was determined by analyzing the frequency distribution of leak acoustic emission events located wavelet transform. At the same time, taking into account the effect of sound velocity on the location of pipeline leakage, the sound velocity of the pipeline was measured and calibrated on site. Finally, the wavelet transform coefficients of the optimal wavelet basis was utilized as the reconstructed signal to carry out the positioning experiment based on cross-correlation. Experimental results show that when the wave velocity of the transverse wave is selected as the sound velocity of the pipeline detection, the wavelet transform coefficient with the optimal wavelet base of "morlet" as the reconstructed signal can eliminate the noise and improve the pipeline positioning accuracy.