Abstract: With the development of aquaculture toward high density and intensification, the accumulation of ammonia nitrogen, nitrate nitrogen, and organic matter in aquaculture effluent has become increasingly prominent. The biofilm method, due to its advantages such as stable operation, resistance to shock loads, and low energy consumption, has become an important technology for the treatment of aquaculture effluent. Among them, the biofilm carrier material plays a key role in microbial adhesion, biofilm stability, and water purification efficiency. This paper systematically reviews the research progress of biofilm carrier materials for aquaculture, focusing on comparing the differences in structural characteristics, engineering adaptability, and pollutant removal performance among inorganic, organic polymer, bio-based, and composite carriers. It also summarizes the typical performance of different carriers in the removal of ammonia nitrogen, nitrate nitrogen, chemical oxygen demand, and total nitrogen. On this basis, the underlying mechanisms through which surface and interface modification strategies such as coating, grafting, and etching in improving hydrophilicity, enhancing microbial colonization, and shear resistance stability are analyzed. Finally, in combination with the engineering characteristics of large water volume, strong load fluctuation and long-term operation of aquaculture effluent, the development direction of biofilm carrier materials in multi-scale structure design, collaborative modification and low-cost large-scale application is prospected, providing a reference for efficient and stable aquaculture effluent treatment.