The invention provides a deep-wave steep-slope welding seam double-laser visual tracking welding device and welding method. The welding device comprises a visual tracking component, a welding component and a controller; the visual tracking component comprises a camera and two laser heads, the two laser heads are positioned on two sides of the camera, structured light planes generated by the laserheads are used for irradiating the surface of a welding seam of a part to be welded, and the camera acquires an image of the welding seam; and the controller is electrically connected with the visualtracking component, determines the actual welding seam position of the part to be welded according to the image, and controls a welding gun of the welding component to weld the part to be welded at the actual welding seam position. Therefore, when the structured light plane of one laser head is shielded, the structured light plane of the other laser head irradiates the surface of the welding seam,so that the visual tracking component can scan the surface of the welding seam without dead angles; and when the structured light plane of any one of the laser heads is shielded by the structure of the piece to be welded, the angle of the laser heads does not need to be adjusted, the time for adjusting the angle of the laser heads is saved, and the welding efficiency is improved.