More and more hydrogen sulfide or ultra-high hydrogen sulfide reservoirs are being developed and utilized, which has attracted much attention to the corrosion problems caused by oil and gas pipelines. Acoustic Emission (AE) is a non-destructive on-line monitoring technology with potential applications for online monitoring of oil and gas pipelines corrosion in acidic environment. Based on the previous studies, the principle of on-line monitoring of acoustic emission and the parameters related to corrosion of oil and gas pipelines in acidic environment, such as counting, absolute energy (ABS), accumulation energy, rise time/amplitude (RA), average frequency (AVG), and amplitude distribution value b were reviewed. Based on these parameters, the process of bubble rupture, pitting corrosion and corrosion cracking, the identification of corrosion types and the location of corrosion sources were analyzed. To a certain extent, acoustic emission on-line monitoring technology can effectively identify the corrosion process, corrosion type and location of corrosion source of oil and gas pipelines in acidic environment, so as to improve the ability of corrosion detection. Therefore, the acoustic emission on-line monitoring technology is of great significance for the corrosion protection and monitoring of oil and gas pipelines in acidic environment.