For narrow gap welding,precise weld deviation information is needed to ensure the problem of welding gun alignment.A magnetic tracking arc-laser sensor combined weld seam tracking system is designed.The front laser vision sensor scans the weld center and adopts the shape.The extraction algorithm and the correlation filter based on Kernel algorithm can obtain the coordinates of the weld feature points.The Lagrange interpolation method is used to fit the approximate curve of the weld trajectory.The threshold threshold is set in two cases.The adaptive weighted fusion method performs information fusion,which makes the acquired weld deviation information more accurate,and finally ensures the centering of the welding torch and the good sidewall fusion.