Objective To determine the galvanic corrosion risk among API X65, 316L and inconel 625. Methods Electrochemical corrosion test, standard galvanic corrosion evaluation experiment and simulation experiment were carried out to analyze the corrosion risk. Results The corrosion potential of X65 was around -0.75 V, while that of 316L and 625 potential was both around -0.35 V. For standard galvanic corrosion evaluation experiment, in the open solution or 100 kPa and 500 kPa CO2 solution, the galvanic current of X65-316L was the largest, followed by X65-625 and then 316L-625. Galvanic corrosion occurred when X65 met either 316L or 625. For simulation experiment, obvious galvanic corrosion occurred among X65, 316L and 625. There was a serious groove corrosion near the weld joint position in X65. The corrosion rate of X65 without galvanic corrosion was 1.24 mm/a. The galvanic corrosion increased this value. The average galvanic corrosion rate of X65-316L was 1.49 mm/a and that of X65-625 was 1.75 mm/a. The local galvanic corrosion rate of X65-316L was 16.8 mm/a and that of X65-625 was 26.4 mm/a, which was over ten times as high as the corrosion rate of X65 without galvanic corrosion. The galvanic corrosion rate of X65 and 316L was larger than that of X65 and 625. There was almost no galvanic corrosion between 316L stainless steel and 625 nickel base alloy. Conclusion Galvanic corrosion risk between X65 and 316L was larger than that between X65 and 625. Galvanic corrosion risk between 316L and 625 was very small.