Thermal　damage　of　malignant　tissue　is　generally　determined　not　only　by　the　characteristics　of　bio-tissues　and　nanoparticles　but　also　the　nanofluid　concentration　distributions　due　to　different　injection　methods　during　magnetic　hyperthermia.　The　latter　has　more　advantages　in　improving　the　therapeutic　effect　with　respect　to　the　former　since　it　is　a　determining　factor　for　the　uniformity　of　nanofluid　concentration　distribution　inside　the　tumor　region.　This　study　investigates　the　effect　of　bio-tissue　deformation　due　to　intratumoral　injection　on　the　thermal　damage　behavior　and　treatment　temperature　distribution　during　magnetic　hyperthermia,　in　which　both　the　bio-tissue　deformation　due　to　nanofluid　injection　and　the　mass　diffusion　after　injection　behavior　are　taken　into　consideration.　The　nanofluid　flow　behavior　is　illustrated　by　two　different　theoretical　models　in　this　study,　which　are　Navier-Stokes　equation　inside　syringe　needle　and　modified　Darcy＇s　law　inside　bio-tissue.　The　diffusion　behavior　after　nanofluid　injection　is　expressed　by　a　modified　convection-diffusion　equation.　A　proposed　three-dimensional　liver　model　based　on　the　angiographic　data　is　set　to　be　the　research　object　in　this　study,　in　which　all　bio-tissues　are　assumed　to　be　deformable　porous　media.　Simulation　results　demonstrate　that　the　injection　point　for　syringe　needle　can　generally　achieve　the　maximum　value　in　the　tissue　pressure,　deformation　degree,　and　interstitial　flow　velocity　during　the　injection　process,　all　of　which　then　drop　sharply　with　the　distance　away　from　the　injection　center.　In　addition　to　the　bio-tissue　deformation　due　to　injection　behavior,　the　treatment　temperature　is　also　highly　relevant　to　determine　both　the　diffusion　duration　and　blood　perfusion　rate　due　to　the　thermal　damage　during　the　therapy.　©　2023　Chinese　Physical　Society　and　IOP　Publishing　Ltd.