Abstract: Submarine pipelines, as a kind of important facility for offshore oil and gas production, play an important role in offshore industries. Regular or timely inspection is required to ensure their safety. ROV is an efficient vehicle for inspection of submarine structures and has been widely used. This paper is to make an introduction to the basic principle and methods of an integrated ROV-based subsea pipeline inspection system. Factors affecting ROV operations and related solutions are discussed according to the practical experiences