Plume　are　common　physical　phenomena　in　fiber　laser　keyhole　welding　and　have　serious　negative　effects　on　the　welding　process.　Based　on　this,　this　paper　explores　the　regulation　law　of　conventional　shielding　gas　flow　on　plume.　The　results　show　that　the　shielding　gas　has　a　very　significant　effect　on　the　suppression　of　the　slender　part　of　the　plume,　and　the　greater　the　gas　flow　rate,　the　better　the　plume　removal　effect.　The　addition　of　the　shielding　gas　makes　the　welding　process　more　stable,　the　molten　pool　flows　stably,　and　the　frequency　of　spatter　eruption　is　reduced.　Under　the　experimental　conditions,　the　optimal　shielding　gas　flow　rate　is　around　15　l/min,　and　the　penetration　depth　and　width　are　increased　by　about　10%　and　decreased　by　about　22%,　respectively,　compared　with　that　without　adding　the　shielding　gas.　Based　on　the　gas　flow　simulation,　the　gas　flow　pressure　(about　132　Pa)　generated　by　an　appropriate　amount　of　shielding　gas　(about　15　l/min)　can　press　the　liquid　column　and　spatter　near　the　keyhole　mouth　into　the　molten　pool　to　avoid　the　spatter　eruption.　Excessive　shielding　gas　flow　will　interfere　with　the　flow　of　the　molten　pool　excessively,　and　the　weld　surface　will　show　a　serious　undercut　phenomenon.