Abstract: Aiming at the problem that it is difficult to automatically plan the welding path and welding attitude at the same time during the robot vision-guided welding process, a robot welding trajectory planning method based on the vision guidance of surface structured light was proposed. The surface structured light vision sensor was fixed at the end of the robot,and the point cloud obtained from the vision sensor was transformed into the robot coordinate system through hand-eye calibration. The point cloud of the complex weldment profile was divided into individual modules by using the differential idea, the obtained point cloud was segmented and fitted based on the random sampling consistency algorithm, the plane equations of different planes of the weldment were derived, the welding path was solved by using the weld seam being on the inter-planar intersecting line, and the welding spatial attitude was solved by the overlap of the vectors of the welding torch and the vectors between the two planes of the weld seam. The welding trajectory of all modules was connected as the robot welding trajectory of the weldment as a whole. The results show that for the welding of 800 mm×180 mm×180 mm weldment,the mean square error of the robot welding point is less than 0.83 mm, which can meet the actual welding requirements.