With the rapid development of mariculture, it plays a more and more important role in global aquaculture. The emission of mariculture wastewater increases sharply, and the nitrogen pollution in mariculture wastewater is serious due to the problems of residues such as bait and feces. The characteristics of many kinds of mariculture and high ion concentration environment in wastewater make it more difficult to purify and treat, which seriously threatens the quality of marine environment and the sustainable development of marine fishery resources development industry. At present, the commonly used nitrification treatment process is mainly to convert ammonia nitrogen into nitrate, which does not effectively remove the ecological risk of mariculture wastewater. Therefore, nitrate removal process is of great significance to the green development of mariculture. Heterotrophic denitrification technology has the advantages of good treatment effect and not easy to produce secondary pollution, which makes it a feasible technology in the treatment of mariculture wastewater, and has been gradually applied by many scholars to purify mariculture wastewater. This paper summarizes the reaction mechanism and advantages of heterotrophic denitrification technology, summarizes and analyzes the research and application of heterotrophic denitrification technology in mariculture wastewater treatment, and analyzes and discusses the factors and reasons affecting the denitrification efficiency of heterotrophic denitrification technology, including carbon source type, hydraulic retention time, temperature and dissolved oxygen. On this basis, the difficulties of heterotrophic denitrification technology applied to Mariculture wastewater treatment are summarized, and the solutions to the existing problems and future research directions are discussed and prospected, in order to provide theoretical basis and technical support for the research of heterotrophic denitrification technology in purifying mariculture wastewater.