Magnetic　field　is　believed　to　have　a　significant　impact　on　the　evolution　of　microstructure　during　solidification　or　service　condition.　Many　researches　apply　magnetic　field　to　obtain　a　material　with　textures　or　special　microstructure,　such　as　turbine　blade.　The　magnetic　field　is　able　to　influence　the　crystal　growth　process,　constrain　crystal　arrangement　direction;　and　effectively　inhibit　the　conductive　fluid　in　thermo　solute　convection.　However,　the　effect　of　magnetic　field　on　the　reliability　of　solder　joint　or　related　research　is　rarely　reported.　The　purpose　of　this　research　is　to　investigate　how　magnetic　field　impact　on　the　microstructure　and　mechanical　performance　of　Sn-based　lead-free　solder　joint.　This　research　contains　two　possible　aspects.　Firstly,　magnetic　field　with　different　intensities　was　posed　on　Sn0.3Ag0.7Cu　to　analyze　the　solidification　microstructure.　The　roles　of　the　second　phase　particles,　such　as　Ni,　were　also　considered.　Intensity　of　magnetic　field　ranged　from　0T-7T.　Secondly,　the　solder　joint　was　subjected　to　current　density　with　magnetic　field.　The　coupling　effect　of　magnetic　and　electric　fields　was　studied.　The　result　indicated　that,　magnetic　field　influenced　migration　rate　and　migration　direction　of　atoms.　Consequently,　the　thicknesses　of　the　intermetallic　compounds　(IMCs)　at　two　interfaces　were　different.　The　appearance　of　interfacial　IMCs　changed.　The　couple　of　magnetic　and　electric　made　the　solder　joint　failure　more　quickly.　This　study　contributes　to　understand　the　reliability　of　solder　joint　under　multi-field　condition.