The utility model provides a corrosion monitoring sensor for gas transportation pipeline, which comprises a sensor housing that is composed of an electrolytic tank cap and an insulation bucket, a nickel bar electrode, and a NaOH electrolyte filled in the insulation bucket, wherein the outer wall of the insulation bucket is provided with at least one concaved arc-shaped test worktop, the upper end of the nickel bar electrode is connected fixedly with the lower end of a shielding lead wire, the portion of the shielding lead wire inside the insulation bucket and the joint of the shielding lead wire and the nickel bar electrode are wrapped by sealant. The corrosion monitoring sensor is not to be affected by the humidity on the metal surface, and has wide measurement range and flexible work means, no sensor needs to be put into the interior of pipeline, operations are made outside the pipeline so as to collect data for measurement by integrating with monitoring instrument, and also no bypass system needs to be arranged, thereby having very convenient use.