In the context of the national "dual-carbon" target, the microalgal-bacterial consortium (MBC) possesses the advantages of simultaneous low-carbon sewage resource recovery and high value-added biomass production, emerging as a promising technology for sustainable wastewater treatment. However, the physical and chemical properties, as well as the activities of MBC, are susceptible to various factors including sewage quality and environmental conditions, leading to unstable sewage treatment performance and limiting its large-scale applications. A deep understanding of the microbial symbiosis mechanism and the factors influeneing MBC function is crucial. Therefore, the principles and characteristics of MBC and in situ MBC technology are compared and analyzed. The interactions between microalgae and bacteria, as well as the mechanisms by which ecological factors influence MBC, are discussed. The common system models and operational characteristies of MBC are also summarized. From an engineering perspective, the research progress of MBC wastewater treatment systems is detailed and explored, with an emphasis on the application of MBC in pilot and engineering seales worldwide. Subsequently, the main technical challenges and application botlenecks facing this technology are analyzed, and the future research direetion and application prospects of MBC technology are discussed.