In 1928, Kubn started using cathodic protection to prevent underground pipelines from corrosion. To date, corrosion control for underground pipelines induced by DC current has been well developed. However, AC corrosion had not been taken into account until two pitting corrosion of a PE coated pipeline were found in Germany 1986. It was proven that an AC transportation system created AC corrosion in forms of pitting on the underground pipeline. Consequently, intensive studies on the corrosivity of AC current on buried structures grew up in the recent years. Even though theories and corrosion control methods for AC corrosion have been proposed in the several researches, lack of knowledge in this field is still present in Taiwan industries. This paper is an attempt to inform the Taiwan pipeline community that AC corrosion on underground pipelines is quite universal also serious. The traditional cathodic protection technology will not control AC corrosion to acceptable levels so that it must simultaneously solve AC corrosion problems to maintain the pipeline integrity.