The utility model discloses a sucker fixing type automatic welding machine, comprising a sucker fixing type rail mechanism, an automatic welding trolley capable of automatically operating along the sucker fixing type rail mechanism, and an automatic control system for controlling the automatic welding trolley. The automatic welding trolley comprises a base; a transmission system for being connected with an external motor and driving the automatic welding trolley along the sucker fixing type rail mechanism to automatically operate is arranged at the bottom end of the base; a welding gun height adjusting system, a welding gun transverse adjusting system and a welding gun angle adjusting system, which are used for adjusting a distance and an angle between a welding gun and a welding seam, are arranged at the top end of the base; and the welding gun height adjusting system, the welding gun transverse adjusting system and the welding gun angle adjusting system are connected with the automatic control system. The sucker fixing type automatic welding machine provided by the utility model has the advantages of simple structure, reasonable design, light weight, convenience in operation, high welding stability and reliability, high welding efficiency, and high welding quality, and is applicable to automatic argon tungsten-arc welding of non-magnetic materials, such as aluminum, titanium, copper, zirconium, tantalum and the like, so that the strong practical applicability can be realized.