The utility model provides an automatic auxiliary device of crossbar circumferential weld, relates to a body of rod circumferential weld automatic welding auxiliary device, especially relates to the circumferential weld automatic welding auxiliary assembly of a crossbar. It including rotatory end with support the end, rotatory end with support the end and fix respectively on the support, its key technology lies in that rotatory hand ladle draws together the base, three -jaw chuck is installed to fixed gear motor and chuck mount pad on the chuck mount pad on the base, three -jaw chuck is connected with gear motor's motor shaft, support the hand ladle and draw together the addendum cone of constituteing by sleeve and the top of suit in the sleeve. The utility model discloses the beneficial effect who has is: it realizes the horizontal steady rotation of the body of rod by the motor drive chuck, makes the welding be in the mean position welding of ideal always, has overcome when welder rotates to the overhead position among the prior art welding seam not good defect that takes shape. Guarantee the not skew welding seam center of welder operation, ensure the weld forming quality.