Abstract: In order to realize seam tracking, detection and closed-loop feedback control of welding torch height and its spatial pose at the same time, which effectively controlled the weld forming quality of welded joints with any different spatial pose, this paper constructed an on-line detection and closed-loop feedback control system of welding torch spatial pose and position based on vision and gravity fusion sensing. Combined with the mathematical detection model, the detection system realized the online real-time detection of the spatial position and pose of the welding torch relative to the workpiece, the spatial pose of the welding torch relative to the direction gravitational acceleration, and the spatial pose of the being welded joint relative to the direction of gravitational acceleration. Results showed the system realized the real-time control of the welding torch spatial pose with an accuracy of 0.1°, and the real-time weld seam lateral tracking and the real-time welding torch height control in the arc welding process with the average deviation of 0.20 mm and 0.78 mm, respectively. Realizing the automatic welding of welded joints with any spatial pose can effectively improve the intelligent level of welding equipment.