Abstract: Traditional methods of saltwater intrusion monitoring are constrained by the spatial distribution of monitoring sites and temporal resolution, making it difficult to achieve extensive and prolonged sequence dynamic monitoring of saltwater intrusion. In recent years, the increasing abundance of remote sensing imagery and rapid development of model algorithms have provided effective supplements to traditional monitoring methods. This review comprehensively discusses the research progress in the field of remote sensing retrieval of surface salinity in the Pearl River Estuary. It begins with a detailed exposition of the main remote sensing data sources and retrieval models currently in use, including low-altitude unmanned aerial vehicles, airborne and spaceborne microwave remote sensing, and spaceborne optical remote sensing. Subsequently, the paper addresses the issues faced by remote sensing technology in supporting saltwater intrusion monitoring from aspects such as model universality, image coverage capability, and vertical salinity monitoring. Finally, future research directions for remote sensing monitoring of water surface salinity in the Pearl River Estuary are analyzed and prospected.