Abstract: In the process of watercraft manufacturing, in order to reinforce the hull,many cubicle is arranged at the bottom of cabin. In cubicle,work environment is narrow and have discontinuous wending seam, all of these will affect welding production efficiency. The existing welding robot can not identify the feature points of drain hole. At present, the welding of cubicle is accomplished mainly by hand. Based on the rotating arc sensor of welding robot, adding laser vision sensor to identify the feature points of drain holes, combining embedded industrial computer, other hardware and VC++ software, to complete the drain hole's automatic identification, tracking and welding. After a large number of experiment verification, the results show that the system is portable, flexible and suitable for cubicle welding operation, recognition and the tracking is effective.