In　order　to　improve　the　overall　performance　indicators,　a　3D　dynamic　simulation　model　of　alternating　current　(AC)　contactors　which　includes　contact　and　electromagnetic　systems　were　built.　At　the　meantime,　the　constitutive　equations,　motion　equations　and　boundary　constraints　were　introduced　into　the　control　equations　for　the　consideration　of　influences　caused　by　the　friction　in　motion　and　the　deformation　during　the　bounce.　And　then,　the　3D　motion　mathematical　model　was　verified　through　the　experiment.　The　focus　is　on　the　bounce　of　its　contact　and　core.　The　result　shows　that　the　3D　model　reflects　the　actual　bounce　of　the　contact　and　core　in　the　closing　process.　Moreover,　through　analyzing　the　influences　of　the　first　and　the　second　bounce　of　the　contact　and　core　by　the　simulation　model,　this　paper　analyzed　the　influences　to　the　bounce　of　the　contact　and　core　which　caused　by　the　close　phase　angle,　voltage,　core　spring,　contact　spring　and　so　on.　And　it　provided　the　theory　basis　for　the　further　study　on　the　suppression　measures　of　bounce　in　the　closing　process.　©　2014　Chin.　Soc.　for　Elec.　Eng.