The　conducted　EMI　simulation　plays　an　important　part　in　the　SMPS　in　the　product　design.　The　analysis　of　common　mode　noise　is　much　more　complex　than　differential　mode　noise.　The　CE　simulation　accuracy　depends　on　the　accuracy　of　CM　mode　noise.　CM　noises　are　determined　by　the　electric　coupling　between　the　voltage　jump　point　and　the　ground.　Traditional　the　CM　models　of　the　electric　coupling　between　the　primary　and　secondary　windings　of　the　transformer　and　between　the　magnetic　components　and　the　ground　is　got　by　tested　with　two-port　equipment　what　are　inconvenient　for　EMI　simulation.　In　this　paper　the　method　by　using　FEA　simulation　method　to　get　the　electric　coupling　between　the　primary　and　secondary　windings　and　the　electric　coupling　between　the　magnetic　components　and　the　ground　without　test　was　proposed.　Finally,　the　consistency　between　the　experiment　results　and　simulation　results　verify　the　proposed　method　to　be　correct　and　feasible.　It　provides　a　new　idea　for　the　modeling　of　the　electric　coupling　for　magnetic　components.　©　2014　IEEE.