Cofiring　of　biomass　and　coal　significantly　reduces　carbon　emissions　and　alleviates　ash-related　problems　of　biomass.　This　study　investigates　the　effect　of　the　biomass/coal　blending　ratio　on　ash　fusion　characteristics　through　the　ash　fusion　test,　X-ray　fluorescence,　and　X-ray　diffractometry.　Meanwhile,　kinetic　analysis　of　the　ash　fusion　process　was　conducted　to　provide　a　new　method　and　reading　benchmark　for　obtaining　precise　and　repeatable　initial　deformation　temperature　(IDT).　Results　showed　that　the　IDT　decreased　with　the　increase　of　the　biomass　blending　ratio　because　of　the　decrease　of　alumina　content　and　the　increase　of　potassium　content.　When　the　biomass　blending　ratio　increased,　the　content　of　orthoclase　and　diopside　at　the　low　melting　point　increased,　while　the　content　of　andalusite,　quartz,　and　anhydrite　at　the　high　melting　point　decreased,　resulting　in　the　decline　of　IDT.　Kinetic　analysis　indicated　that　with　increasing　biomass　blending　ratio,　the　activation　energy　of　ash　fusion　reaction　decreased,　which　is　the　essential　reason　for　the　decrease　of　IDT.　Coal　ash　had　an　activation　energy　of　1144.67　kJ·mol-1,　while　it　decreased　to　145.89　kJ·mol-1　with　an　increased　biomass　blending　ratio　to　100%.　Compared　with　the　larger　error　(up　to　60　°C)　caused　by　visual　reading　on　the　morphological　change　of　the　triangle　ash　cone,　kinetics　calculation　gave　precise　prediction　with　less　error　between　2　and　7　°C.　As　an　optimal　recommendation,　the　average　shrinkage　rate　of　height　at　41%　could　be　used　as　a　reading　benchmark　for　the　determination　of　IDT　in　further　study.　Copyright　©　2019　American　Chemical　Society.