The invention provides a method for welding an anticorrosion steel pipeline with no internal repaired mouth, which is applicable to the anticorrosion treatment of a steel pipeline welding connector with an anticorrosion coating in the petroleum industry and the chemical industry. The method is characterized in that a groove with a certain length and depth is machined on a position which is at a certain distance from the end part of the steel pipe, an anticorrosion alloy material is surfaced on the groove, the end part of the surfaced steel pipe is machined into a V-shaped groove, an anticorrosion coating with sufficient thickness is coated on the inner wall of the steel pipe, the anticorrosion coating covers sufficient length of the anticorrosion alloy surfacing layer, then two steel pipes are in butt connection with each other, layering welding is carried out after the two steel pipes are fixed on one point, an argon tungsten-arc welding method is adopted, the anticorrosion alloy material which is identical to that of the surfacing is selected as the filling material, and argon is filled into the pipe to protect the pipe in the welding process. Due to the adoption of the novel technology for welding the anticorrosion steel pipeline with no internal repaired mouth, the corrosion resistance of the inner wall and a weld mouth of the pipeline can be guaranteed, the internal mouth repairing technology on the spot after the welding can be avoided, characteristics such as simplicity in construction and reliability in performance can be realized, and the method is suitable for the real engineering application of the petroleum and chemical industry fields.