Heterotrophic　nitrification-aerobic　denitrification　(HN-AD)　is　a　novel　alternative　for　nitrogen　removal　due　to　simultaneous　nitrification　and　denitrification　that　occurs　under　aerobic　conditions.　Until　now,　ways　in　which　to　achieve　aerobic　nitrogen　removal　from　wastewater　via　the　HN-AD　process　have　not　been　fully　explored.　In　this　study,　autotrophic　nitrification　was　converted　into　HN-AD　in　a　halophilic　aerobic　granular　sludge　(HAGS)　system　when　the　wastewater　salinity　decreased　from　30　to　20　g/L.　Bacteria　affiliated　to　the　genus　Paracoccus　were　dominant　in　the　HAGS　with　a　relative　abundance　of　56%,　functioning　with　HN-AD.　Accordingly,　the　indicative　gene　napA　encoding　for　HN-AD　was　5.1　x　10(9)　copies/g　HAGS.　HAGS　performing　HN-AD　exhibited　a　stable　total　inorganic　nitrogen　(TIN)　removal　efficiency　performance　in　response　to　salinity　variations　of　10-40　g/L,　owing　to　the　stable　HN-AD　functional　community.　The　significant　inhibition　of　HN-AD　was　observed　in　both　low　salinity　(&　LE;5　g/L)　and　high　salinity　(&　GE;50　g/L)　conditions,　accompanied　by　the　disintegration　of　granules.　Granular　disintegration　was　triggered　by　the　lower　secretion　of　extracellular　polymeric　substances　and　alginate-like　exopolysaccharides.　HAGS　performing　HN-AD　could　simultaneously　remove　chemical　oxygen　demand　and　TIN　from　saline　wastewater　in　a　single　aerobic　tank,　thus　reducing　the　construction　and　operation　costs.