Abstract: In order to solve the problems of abrading easily, loud noise and low stability of the mechanical arc sensor, a new method of seam-tracking with appending magnetic-control welding arc technology was presented and its basic principle was discussed. Based on the eleetromagnetic fields theory and magnetic-control law, the relationship of parameters was also analyzed.To obtain signals of welding current by Hall sensor, the Butterworth filter hardware filtering and the current of signal software handling method with wavelet analysis methods was utilized.The measured current signals of such three methods as magnetic-control swing-arc, without magnetic field and mechanical rotatable-arc were analyzed, respectively, and the effective intorral twice romove extreme integral contrast method was used to extract actual seam deviation information.Results of these tests show that the magnetic-control arc sensor for seam tracking correct feasible can achieve good effect in tracing control and provide a potential direetion for the current seam-tracking technology.