The　precision　of　magnetic　field　calculation　is　crucial　to　predict　the　arc　behavior　using　magnetohydrodynamic　(MHD)　model.　A　integrated　calculation　method　is　proposed　to　couple　the　calculation　of　magnetic　field　and　fluid　dynamics　based　on　the　commercial　software　ANSYS　and　FLUENT,　which　especially　benefits　to　take　into　account　the　existence　of　the　ferromagnetic　parts.　An　example　concerning　air　arc　is　presented　using　the　method.