Abstract: With the development of pipeline business and technology, more and more pipeline-related terms, such as long-distance pipeline, pipeline and pipeline system, appear in the codes, standards, scientific reports and papers.However, arbitrary terms using and inconsistent definitions are very common, which may lead to statistical data deviation, difficulty in comparison and non-uniform terms in standards and regulations.To settle this issue, the current standards and regulationgs in China and overseas were collected and analyzed.Based on the comparative study of the classification of pipelines, the definition and coverage of the terms in relation to the pipeline, pipeline system and long-distance pipeline were compared and studied.The differences of these terms were pointed out, and suggestions on the definition and English expressions were proposed for pipeline-related series terms uniformly defined in the oil and gas energy industry.