Flange welding positioning tool

The invention relates to the technical field of tool clamps, and discloses a flange welding positioning tool. The flange welding positioning tool comprises a main shaft, wherein a holding handle is arranged at the rear end of the main shaft, a center hole is formed in the main shaft, a center shaft is arranged in the center hole, a first connecting ring is fixed to the outer side of the main shaft, and a second connecting ring is rotationally arranged at the front end of the center shaft; three sets of connecting arms are arranged on the outer sides of the first connecting ring and the second connecting ring, a pipeline supporting base is arranged between the outer ends of each set of connecting arms, and a first driving mechanism for driving the center shaft to move along the center hole is arranged at the rear end of the center shaft; a third connecting ring is further fixed to the main shaft, the rear end of the main shaft is sleeved with a sleeve, a fourth connecting ring is rotationally arranged at the f