This　study　investigated　the　relationship　between　acyl　homoserine　lactones　(AHLs)-based　quorum　sensing　(QS)　and　the　properties　of　Anammox　granular　sludge　at　low　temperatures　(11-23°C).　Results　indicated　that　adding　different　concentrations　of　AHLs　inhibitors　reduced　the　content　of　N-hexanoyl-dl-homoserine　lactone　(C6-HSL)　and　N-octanoyl-dl-homoserinelactone　(C8-HSL)　in　Anammox　granules　on　different　degrees　at　different　operation　temperatures,　which　led　to　the　deterioration　of　granules　stability　and　activity.　The　important　role　of　endogenous　C6-HSL　and　C8-HSL　signals　in　maintaining　Anammox　granular　sludge　stability　and　activity　in　low-temperature　conditions　was　revealed.　In　addition,　in　the　process　of　reducing　operation　temperatures,　another　type　of　AHL　signal　(N-(3-oxooctanoyl)-l-homoserine　lactone,　3OC8-HSL)　was　released　by　Anammox　granules.　The　effects　of　exogenous　C8-HSL　on　the　strength,　average　diameter,　and　density　of　Anammox　granules　were　closely　related　to　the　operation　temperature.　When　the　operation　temperature　ranged　from　11°C　to　16°C,　the　stability　of　granules　could　be　significantly　improved　by　exogenous　C8-HSL.　In　addition,　the　addition　of　C6-HSL　and　3OC8-HSL　promoted　the　activity　of　Anammox　granules　when　the　operation　temperatures　of　the　reactors　were　11-23°C.　This　study　proposed　a　novel　approach　to　improve　the　properties　of　Anammox　granules　at　low　temperatures　from　the　perspective　of　QS.　PRACTITIONER　POINTS:　Endogenous　AHLs　played　an　important　role　in　maintaining　the　activity　and　stability　of　Anammox　granules　at　11-23°C.　Exogenous　C8-HSL　improved　the　granules　stability　at　the　low　temperature　of　11-16°C.　Exogenous　C6-HSL　or　3OC8-HSL　promoted　the　granules　activity　at　11-23°C.　Supply　a　novel　way　to　improve　the　Anammox　granules　performance　at　low　temperatures.