In the practical experiment to electrical signal of submerged arc welding process, it is difficult to avoid noises, so an important step is to eliminate the disturb of noise. Based on the wavelet algorithm, wavelet packet filtering method is analyzed in this paper. It has been proved by the experiments that the wavelet packet filtering based on soft threshold is a better de-noising method, Filtering electric signal of submerged arc welding by wavelet packet filtering method can keep the break position of the signal, and it can improve the effect of extracting signal characteristics.