Plume　is　an　inherent　physical　phenomenon　in　fiber　laser　keyhole　welding,　negatively　affecting　welding　quality.　This　paper　proposes　a　new　type　of　high-speed　shielding　gas　microbeam　(HSGM)　based　on　the　limitation　of　conventional　shielding　gas　regulating　plumes.　The　gas　flow　characteristics　of　the　HSGM　on　the　molten　pool　surface　were　explored　using　numerical　simulation.　Then,　the　coaxial　double-layer　shielding　nozzle　was　trialmanufactured　to　clarify　the　regulation　law　for　the　HSGM　on　the　plume.　The　gas　velocity　and　pressure　produced　by　the　HSGM　on　the　molten　pool　surface　were　positively　correlated　with　the　shielding　gas　flow　rate,　and　the　gas　flow　pattern　was　an　acute　triangle　shape.　The　suitable　HSGM　can　significantly　restrain　plume　formation,　improve　the　weld　surface　forming　quality,　increase　the　weld　penetration　depth　(about　15.4%),　and　reduce　the　mass　loss　of　the　weld　(about　58.7%).　The　significant　blowing　pressure　effect　of　HSGM　on　plumes　and　splashes　was　the　key　to　regulating　the　welding　process.　Compared　with　conventional　shielding　gas,　the　use　of　HSGM　was　significantly　reduced.