The utility model discloses a soil corrosion sensor for pipelines. The sensor at least comprises a detection element and a target material positioned outside the detection element, wherein the detection element comprises a detection electrode with a sensitive film wrapped outside, and the target material can be selected according to the requirement of users and processed and manufactured according to the alarming depth required by the users. The sensor is placed outside the pipelines to detect the old or new pipelines, so that the corrosion of pipelines can be learned in time. The sensor can be used for detecting not only local corrosion but also uniform corrosion of pipelines, that is, both the uniform corrosion and non-uniform corrosion can be detected.