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　degrees　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　degrees　C　to　16　degrees　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　degrees　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　degrees　C.　Exogenous　C8-HSL　improved　the　granules　stability　at　the　low　temperature　of　11-16　degrees　C.　Exogenous　C6-HSL　or　3OC8-HSL　promoted　the　granules　activity　at　11-23　degrees　C.　Supply　a　novel　way　to　improve　the　Anammox　granules　performance　at　low　temperatures.