Anammox　granular　sludge　(AnGS)　systems　efficiently　remove　nitrogen　from　saline　wastewater,　but　their　adaptation　mechanisms　to　salt　stress　are　unclear.　This　study　explores　the　adaptability　of　the　AnGS　system　when　exposed　to　salinity　(0–30　g　NaCl/L),　focusing　on　the　role　of　N-acyl　homoserine　lactone-mediated　quorum　sensing　(AHL-QS)　in　microbial　responses　and　community　symbiosis　under　stress.　Based　on　Hill　model　assessments,　AnGS　tolerates　salt　stress　up　to　15.73　g/L.　Within　this　range,　AnGS　maintains　cellular　stability　by　enhancing　extracellular　polymeric　substances　(EPS)　release,　regulating　oxidative　stress;　and　drives　nitrogen　metabolism　by　increasing　cytochrome　c-activity　to　maintain　electron　transfer.　With　the　mantel　test　and　validation　experiments,　salt　stimulates　QS,　leading　to　increased　AHL　(C6-HSL　and　C8-HSL)　secretion　associated　with　EPS　release,　extracellular　electron　transfer,　and　oxidative　stress.　Stabilization　of　AHL-QS　genera　supports　AHL　secretion　and　microbial　symbiosis,　promoting　AnGS　adaptation　to　salt　stress.　These　insights　facilitate　optimizing　AnGS　for　saline　wastewater　treatment.　©　2024　Elsevier　Ltd