The　effects　of　different　magnetic　field　excitation　currents　on　the　solidification　microstructure　and　mechanical　properties　of　ZL205A　alloy　were　investigated　by　using　downward　traveling　wave　magnetic　field,and　the　evolution　law　of　θ　phase　was　analyzed.　The　results　show　that　the　traveling　wave　magnetic　field　can　refine　the　alloy　structure　to　form　fine　near-equiaxed　crystal　structure,　and　improve　the　tensile　strength　and　elongation　of　ZL205A　alloy.　Meanwhile,　the　excitation　current　of　the　magnetic　field　has　a　direct　effect　on　the　refinement　effect　of　solidification　structure.　With　the　current　frequency　of　50　Hz,　the　desirable　excitation　current　for　ZL205A　alloy　is　in　range　of　10~20　A.　In　addition,　with　the　increase　of　the　excitation　current,　the　θ　phase　appears　to　be　paramagnetic　in　the　magnetic　field.　As　the　magnetic　field　increase,　the　nucleation　undercooling　degree　is　increased,　so　the　nucleation　rate　is　increased　and　θ　phase　is　broken　down.　When　the　excitation　current　is　less　than　10　A,　the　electromagnetic　force　generated　by　the　magnetic　field　has　a　great　influence　on　the　size　of　the　θ　phase.　When　the　magnetic　current　is　20　A,　the　melt　viscosity　is　increased　as　a　result　of　the　magnetic　field　Lorentz　force,　which　can　prevent　the　θ　phase　from　further　refinement.　©　2019,　Journal　Office　of　Special　Casting　and　Nonferrous　Alloys.　All　right　reserved.