Due　to　the　increasingly　urgent　demand　for　effective　wastewater　denitrification　and　dephosphorization　systems,　there　is　a　need　to　improve　the　performance　of　existing　biological　treatment　technologies.　As　a　bacteria-level　communication　mechanism,　quorum　sensing　(QS)　synchronizes　gene　expression　in　a　density-dependent　manner　and　regulates　bacterial　physiological　behavior.　On　this　basis,　the　QS-based　bacterial　communication　mechanism　and　environmental　factors　affecting　QS　are　discussed.　This　paper　reviews　the　influence　of　QS　on　sludge　granulation,　biofilm　formation,　emerging　contaminants　(ECs)　removal,　and　horizontal　gene　transfer　in　sewage　treatment　system.　Furthermore,　the　QS　inhibition　strategies　are　compared.　Based　on　the　coexistence　and　balance　of　QQ　and　QS　in　the　long-term　operation　system,　QQ,　as　an　effective　tool　to　regulate　the　growth　density　of　microorganisms,　provides　a　promising　exogenous　regulation　strategy　for　residual　sludge　reduction　and　biofilm　pollution　control.　This　paper　reviews　the　potential　of　improving　wastewater　treatment　efficiency　based　on　QS　theory　and　points　out　the　feasibility　and　prospect　of　exogenous　regulation　strategy.　Practitioner　Points　The　mechanism　of　bacterial　communication　based　on　QS　and　the　environmental　factors　affecting　QS　were　discussed.　The　application　of　QS　and　QQ　in　improving　the　sludge　performance　of　biological　treatment　systems　was　described.　The　significance　of　QS　and　QQ　coexistence　in　sewage　treatment　process　was　described.