This　work　proposed　a　novel　strategy　via　heat-assisted　potassium　ferrate　(PF)　pretreatment　to　enhance　methane　production　from　waste　activated　sludge　(WAS)　during　anaerobic　digestion.　In　this　research,　five　dosages　of　PF　(i.e.,　0,　0.05,　0.1,　0.3　and　0.5　g/g　VSS)　at　two　temperatures　(i.e.,　25　°C　and　55　°C)　were　explored.　Biochemical　methane　potential　experiments　illustrated　that　heat-assisted　PF　pretreatment　improved　cumulative　methane　production　with　the　maximum　yield　up　to　163.93　mL　CH4/g　VSS,　149.0　%,　119.6　%　and　121.0　%　of　that　in　the　control,　individual　0.5　g　PF/g　VSS　and　individual　heat　(i.e.,　55　°C)　pretreatment　digesters,　respectively.　The　maximum　methane　potential　(B0)　was　promoted　by　63.2　%　with　heat-assisted　PF　pretreatment　compared　to　the　control,　while　the　hydrolysis　rate　(k)　changed　slightly.　Mechanism　analysis　revealed　that　heat-assisted　PF　pretreatment　accelerated　WAS　solubilization　and　enhanced　the　biodegradability　of　released　substances,　providing　more　available　matrix　for　bacteria　during　the　following　anaerobic　digestion　processes.　Microbial　community　analysis　exhibited　that　several　microbes　such　as　Proteiniclasticum　sp.,　Sedimentibacter　sp.　and　Methanosaeta　sp.　associated　with　hydrolysis,　acidification　and　methanogenesis　respectively　were　improved　after　heat-assisted　PF　pretreatment.　In　addition,　the　relative　bioactivities　of　protease,　butyrate　kinase　and　acetate　kinase　were　also　increased.　Furthermore,　variation　of　dominant　genes　associated　with　methane　production　indicated　that　acetate-dependent　methanogenesis　was　the　main　pathway　while　CO2-dependent　methanogenesis　pathway　was　inhibited　by　heat-assisted　PF　pretreatment.　©　2022　Elsevier　B.V.