The invention relates to a welding device for an oil injector support plate and a round tube. The welding device comprises a bottom plate (1), a round tube fixing groove (2), a support plate press plate (3), air cylinders (4), pressers (5) and welding guns (6), wherein the round tube fixing groove (2) is fixed on the bottom plate (1), the support plate press plate (3) is arranged above the round tube fixing groove (2), the air cylinders (4) are in transmission connection with the pressers (5), and the welding guns (6) are aligned to the to-be-welded support plate and the to-be-welded round tube; the support plate is placed after the round tube is placed into the round tube fixing groove (2), the support plate is tightly pressed by the support plate press plates (3), meanwhile, the round tube is tightly pressed by the pressers (5), and the welding guns (6) are aligned to the support plate and the round tube to perform welding. Compared with the prior art, the welding device has the advantages of high welding efficiency, high product welding quality, safety, reliability and the like.