Abstract: A new filtering method for magnetic control submerged arc welding, second-order Butterworth low-pass filtering method was introduced, and its filtering effect was compared to the traditional filtering methods such as simple low-pass filter method and software median filtering method. The results show that second-order Butterworth low-pass filtering method not only can filter the useless noise signal, but also can keep the original signal features well, and its filtering effect is better than the two kinds of traditional filtering methods and can well meet the continuously improved welding quality requirements.