Abstract: A signal processing with the wavelet analysis is introduced. According to its characteristics of time-frequency localization and multi-resolution, the wavelet transform is a useful and effective method in the singularity detection and transient analysis of the signal and acquiring of non-steady information under a seriously periodic interference. It is especially useful in increasing the SNR of reconstructed signal by the prior wavelet packet basis acquired with a self-defined cost function for the eddy current inspection of hole defects in the long distance oil pipeline.