Magnetic　fields　have　been　widely　used　in　the　application　of　bioengineering,　and　are　expected　to　distribute　as　uniformly　as　possible　in　order　to　achieve　more　effective　treatment.　The　solenoid　coil　is　one　of　the　most　popular　devices　used　for　producing　magnetic　fields.　However　it　has　proved　difficult　to　achieve　a　uniform　profile　in　a　limited　length　with　this　approach.　This　paper　proposes　an　optimization　method　to　improve　the　uniformity　of　the　magnetic　field　for　a　solenoid　coil　by　considering　two　correcting　coils,　which　are　optimized　by　using　a　simulated　annealing　algorithm　for　its　characteristic　parameters.　The　results　after　the　optimization　will　further　be　considered　in　order　to　analyse　the　therapeutic　effect　on　a　proposed　bio-tissue　model　during　magnetic　hyperthermia.　The　magnetic　field　distribution　inside　the　solenoid　is　obtained　using　Maxwell＇s　theory,　and　the　treatment　temperature　of　the　tumor　model　is　determined　using　Pennes＇　bio-heat　transfer　equation.　Simulation　results　demonstrate　that　the　uniformity　of　the　magnetic　field　can　be　significantly　improved　using　the　proposed　method,　and　that　when　considering　this　optimization,　the　treatment　temperature　profile　presents　a　better　result　compared　with　a　single　solenoid.　©　2020　IOP　Publishing　Ltd.