There are two advantages including high accuracy and strong freeinterference for the magnetoacoustic synchronous method, which is a fine location method and is widely used. However, it is difficult to effectively detect the audio signal. Because the wavelet packet transform in detecting whether the normal signal contains a anomaly transient or not , an audio signal enhancement algorithm based on wavelet packet transform decomposing signal, adaptive filter estimating noise and genetic algorithm optimizing signal combined reconstructing signal is presented. The adaptive filter needs less for prior knowledge of the signal and noise, and genetic algorithm does not depend on the specific problems. Experimental results validate its high accuracy and strong robustness. In particular, it can be applied to the extracting audio signal under the condition that the cable fault discharge is weak. Therefore, it is a potential eligible solution to strict constraint of the background noise and narrow recognition range in pinpointing of cable failure location.