Abstract: The traditional teaching welding method has a cumbersome operation process, which leads to low efficiency and high dependence on manual labor. To address these issues, this paper proposed a non-teaching automatic welding system based on DXF file parsing and point cloud data processing. The system parses the DXF file of the workpiece to obtain the ideal weld position and weld type information, and achieves the initial positioning of the robot weld by solving the multi coordinate system transformation relationship. On this basis, a laser vision sensor welding point cloud acquisition method considering real-time robot pose is proposed, and a point cloud welding seam detection algorithm based on plane detection is developed to obtain actual welding seam position information and achieve robot non-teaching welding. The results showed that the system can accurately obtain the point cloud information of the weldment, and the error of the weld seam extraction method is less than 0.16 mm, which meets the welding requirements.