Parasocial Interaction (PSI) refers to the unilateral social relationship between media audiences and media roles, which is a core concept in media research. Some scholars have conducted research on it in the offline media environment, but here hasn't been a comprehensive review of comparable content in the online media environment. In light of this, this article covers existing research in the areas of connotation, features and measurement, theoretical mechanism, pre-factors, and outcome variables of PSI, and speculates on future study directions.