Abstract: According to the characteristics of submerged arc welding with alternative wire feed system, the seam tracking process of the submerged-arc welding was studied.The models to simulate welding power, welding arc and scaming the V groove were founded, and the general simulation model of welding system was established based on these models.The influences of groove typt, welding power and forms of metal transfer on the output welding current were studied and the effects of the main parameters of arc sensor on seam deveiation and welding parameters were also analyzed.The studies offer a theoretical foundation to the establish the auto seam tracking sy stem of weaving arc sensor in submerged arc welding.