The invention discloses a double-beam laser TIG composite welding process for thin plate butt welding net forming, and the double-beam laser TIG composite welding process is suitable for butt welding of a thin plate. A provided welding method is suitable for realizing butt welding net forming of the thin plate under a butt joint clearance condition, and defects such as the sinking, the undercut, the back protrusion and splash which are prone to appear in a butt welding process are overcame. The process is characterized in that a butt welding seam serves as a center, incidence of double laser beams is conducted obliquely, and focuses of the double laser beams are symmetrically distributed on mental base materials at the two sides of the butt clearance; and a centre line of a TIG electric arc is in the same plane as a centre line of the butt welding seam and has a certain angle with a plate face; during the welding, the TIG electric arc is located at the rear side of the perpendicular bisector of the connection line of the focuses of the double laser beams. Compared with the traditional laser butt welding method, the clearance adaptability of the double-beam laser TIG composite welding process for thin plate butt welding net forming is greatly improved in the thin plate butt welding process, the weld width of a welding seam is obviously increased, surface forming and back forming of the welding seam are significantly improved, and the defects of back splash, protrusions and the like are effectively suppressed.