Abstract The wastewater from mariculture is characterized by low levels of potential pollutants and nutrient loads compared with industrial effluents. However, with elevated nitrogen and phosphorus ratios, the presence of persistent antibiotics, and endocrine‐disrupting compounds at ecologically relevant concentrations, mariculture wastewater can cause chronic and serious harm to the marine environment, including elevated nutrient load of the water body and a polluted ecosystem. Physical, chemical, and biological methods can be used to treat mariculture wastewater. Among them, physical and chemical methods have certain limitations, such as high cost and generating secondary pollutants. In contrast, biological methods are environmentally friendly, while a comprehensive summary of biological methods for mariculture wastewater treatment is limited. To fill this knowledge gap, we summarize basic principles and recent progress of biological treatment techniques for mariculture wastewater. Microbial technology and plant treatment technology are the most effective techniques for mariculture wastewater treatment. Multiple technique coupling processes, such as bacteria‐algae and membrane‐biofilm systems, are future trends in treating mariculture wastewater for discharge or recycle, which need further investigations.