Abstract: In order to reduce the residual height of the outer weld of the spiral SAW pipe so as to properly control the outer weld morphology of the pipe,and save anti-corrosion coating material,a kind of full outer weld grinding machine is designed,and actually developed.The grinding machine is composed of three major units,i.e.,the abrasive-belt grinding mechanism,the displacement mechanism and the frame,being capable of on-line continuous grinding of the full outer weld of the spiral SAW pipe.The belt grinding mechanism is used for mechanically grinding the full outer weld of the pipe,the displacement mechanism is used for reciprocating movement of the machine as a whole.The said full outer weld-grinding machine for the spiral SAW pipe features continuous,hi-efficiency and consistent operation,resulting in even residual weld height and good morphological transition of the weld.