Positioning device for welding water outlet elbow pipe of long shaft pump

The embodiment of the utility model provides a positioning device for welding a water outlet elbow of a long shaft pump. The positioning device comprises a base, a reference shaft and a positioning assembly. The reference shaft is arranged on the base and comprises a matching part. And the positioning assembly is movably connected with the matching part, and the positioning assembly is configured to move in the axial direction and the radial direction of the reference shaft so as to adjust the to-be-welded part to a target position for positioning and welding to form the water outlet elbow. When the positioning assembly moves in the axial direction of the reference shaft, the to-be-welded part can be driven to move to a target position in the axial direction, and therefore the distance between the to-be-welded part in the axial direction can be quickly and accurately positioned and adjusted. When the positioning assembly moves in the radial direction of the reference shaft, the to-be-welded part can be driven