A　new　approach　has　been　investigated　by　using　an　external　electric　current　technique　in　CO2　laser　beam　welding　of　aluminum　alloys.　Connecting　the　filler　wire　with　one　pole　of　a　DC　power　supply　and　the　workpiece　with　the　other,　a　closed　electric　circuit　was　built.　By　this　means,　the　wire　is　resistively　preheated　and　a　magnetic　field　and　electromagnetic　forces　are　generated　in　the　weld　pool.　It　is　found　that　the　weld　depth　and　area　increase　considerably,　the　weld　seam　becomes　more　slender,　the　plasmas　are　shrunk　and　the　processing　stability　is　improved　with　the　increase　of　the　current.　Further　experimental　results　demonstrate　that　these　influences　do　not　result　from　the　resistive　heat　from　the　wire,　but　the　electromagnetic　effects.　This　new　approach　provides　a　possibility　to　increase　the　processing　efficiency　and　flexibility,　improve　the　process　stability　and　weld　quality,　and　also　shape　the　seam　cross　section.