The　treatment　magnetic　field　usually　presents　an　inhomogeneous　distribution　inside　a　real　therapeutic　equipment　during　magnetic　hyperthermia,　which　will　ultimately　affect　the　treatment　effects　due　to　its　unsatisfactory　distribution　of　treatment　temperature　inside　tumor　region.　However,　previous　literature　has　paid　less　attention　to　optimize　the　uniformity　for　magnetic　field　device　and　also　to　investigate　its　influences　on　the　treatment　effect　during　magnetic　hyperthermia.　Furthermore,　the　magnetic　nanoparticles　(MNPs)　concentration　under　the　same　magnetic　fluid　dose　is　expected　to　have　a　value　as　small　as　possible　in　order　to　reduce　the　effect　of　the　MNPs　residual　inside　bio-tissue,　which　however　was　also　rarely　reported　by　the　existing　researches.　This　article　investigates　the　therapeutic　magnetic　field　for　circular　and　square　Helmholtz　coil　devices,　analyzes　the　influence　of　magnetic　field　uniformity　on　the　therapeutic　effect　by　evaluating　the　temperature　distribution　of　biological　tissue　due　to　the　applied　magnetic　field,　and　also　discusses　the　influence　of　different　magnetic　fields　on　the　cumulative　equivalent　heating　minutes　at　43℃　under　two　different　blood　perfusion　rates.　In　addition,　this　study　proposes　an　improved　particle　swarm　optimization　algorithm　considering　several　constraints　in　order　to　obtain　the　minimum　volume　fraction　of　MNPs　at　the　injection　point　and　the　corresponding　optimized　properties　for　MNPs　radius　and　magnetic　field　at　this　time.　The　proposed　constraints　involved　in　this　study　consist　of　the　maximum　safe　temperature　for　treatment,　the　safe　upper　limit　of　treatment　magnetic　field,　the　size　range　of　MNPs,　and　the　effective　conditions　for　MNPs　heat　generation.　The　partial　differential　equations　involved　magnetic　field　and　temperature　field　are　solved　using　finite　element　method　for　the　proposed　Helmholtz　coil　devices　and　a　three-dimensional　mouse　model,　respectively.　The　MNPs　inside　the　proposed　tumor　region　are　assumed　to　have　a　Gaussian　distribution　centered　on　the　injection　point.　Simulation　results　demonstrate　that　the　final　optimization　results　considering　the　proposed　method　meet　the　requirements　of　proposed　constraints,　which　are　0.009　96　for　the　volume　fraction　of　MNPs　at　the　injection　point,　50kA/m　for　the　magnetic　field　intensity,　100kHz　for　the　magnetic　field　frequency,　and　7.005nm　for　the　radius　of　MNPs　during　therapy.　Both　circular　and　square　Helmholtz　coils　can　generate　a　uniform　magnetic　field　near　the　coil　center　while　tend　to　have　an　inhomogeneous　distribution　away　from　the　coil　center.　In　comparison,　the　square　Helmholtz　coil　presents　a　better　uniformity　in　magnetic　field　distribution　away　from　the　coil　center　with　respect　to　the　circular　one.　This　characteristic　is　also　mirrored　in　the　treatment　temperature　distribution　and　ultimately　the　treatment　effect.　In　addition,　the　case　considering　the　temperature-dependent　blood　perfusion　rate　presents　a　higher　cumulative　equivalent　heating　minutes　at　43℃　than　the　case　considering　a　constant　one　under　the　three　different　magnetic　fields.　The　following　conclusions　can　be　drawn　from　the　simulation　analysis:　(1)　The　circular　Helmholtz　coils　can　have　a　better　performance　in　the　magnetic　field　uniformity　with　respect　to　the　square　Helmholtz　coil,　and　this　characteristic　is　also　true　for　the　treatment　temperature　distribution　and　the　treatment　effect　during　magnetic　hyperthermia.　(2)　The　proposed　method　based　on　the　improved　particle　swarm　optimization　algorithm　can　not　only　meet　the　safe　criterions　of　maximum　treatment　temperature　and　the　magnetic　field　but　also　obtain　a　far　less　volume　fraction　of　MNPs　than　the　classical　value.　(3)　Temperature-dependent　blood　perfusion　rate　can　result　in　an　overall　higher　treatment　temperature　distribution　and　thermal　damage　for　malignant　tissue　with　respect　to　a　constant　one　in　the　same　therapeutic　condition.　©　2023　Chinese　Machine　Press.　All　rights　reserved.