The　relationship　between　granular　size　and　anaerobic　ammonium　oxidation　(anammox)　performance　in　the　anammox　granular　sludge　(AnGS)　system　has　been　extensively　observed.　However,　the　metabolic　pathways　regulated　by　commu-nication　and　cross-feedings　among　anammox　consortia　remain　unclear.　The　reactor　operation　and　metabolomics　anal-yses　were　combined　to　explore　the　influence　of　microbiota　cooperation　on　metabolic　pathways　and　granule　properties　under　low　temperature　(18　degrees　C)　and　nitrite　inhibition.　Anammox　activity　was　sustained　under　challenging　circum-stances　by　active　quorum　sensing　among　anammox　consortia　in　AnGS　with　diameters　larger　than　1.4　mm,　which　pro-moted　nucleotide　metabolism.　Cross-feedings　among　anammox　consortia　increased　the　levels　of　molybdopterin　cofactor　and　folate　meanwhile　decreasing　the　cost　of　carbon　fixation　metabolism,　which　supported　anabolism　and　maintained　the　content　of　heme　c　and　extracellular　polymeric　substance.　These　metabolic　insights　into　the　AnGS　system　provide　a　new　view　for　anammox　process　overcoming　the　low　temperature　and　nitrite　stress.