Abstract: Under the "Dual Carbon" strategy and the land‑sea integration policy, there is an urgent need for synergistic control technologies that combine high‑efficiency nitrogen removal with low carbon emissions to address the persistent threats of eutrophication and frequent harmful algal blooms caused by coastal nitrogen pollution. Anaerobic ammonium oxidation (Anammox) exhibits great potential for pollution and carbon reduction in coastal nitrogen control due to its advantages of no external carbon requirement, low aeration energy consumption, and low sludge production. Based on available research, the current status of coastal nitrogen pollution was summarized, and the advantages and disadvantages of traditional nitrogen removal and Anammox technologies in pollution control and carbon reduction were compared. The effects of salinity stress and multi‑factor interactions on nitrogen removal performance were also highlighted. The salinity adaptation mechanism of anammox bacteria was elucidated at multiple scales, including genomic characteristics, physiological regulation, cellular structure, and community interactions. The inherent salt tolerance of marine Ca. Scalindua lineages enabled their direct application in coastal nitrogen removal without prolonged acclimation. Regulation strategies such as inoculum optimization, operational parameter control, process innovation, and exogenous enhancement were discussed, and a full‑chain synergistic pathway from watershed to estuary to coastal sea for pollution and carbon reduction was proposed. Finally, perspectives were provided on mechanism breakthroughs, process innovation, digital empowerment, and policy support to facilitate the transformation of coastal nitrogen pollution control from a high‑carbon, energy‑intensive mode to a low‑carbon, resource‑oriented paradigm.