The　control　of　brass　welding　porosity　is　studied　by　adopting　a　new　method　of　the　intermediate　transition　layer.　The　weld　porosities　of　brass　laser　welding　under　the　copper　intermediate　layer　condition　and　brass　general　butt　laser　welding　are　contrasted　and　analyzed.　The　research　results　reveal　that　the　porosities　of　weld　surface　and　weld　interior　are　greatly　reduced　under　the　condition　of　the　intermediate　layer.　As　the　welding　speed　increases,　the　porosity　decreases　gradually.　The　porosity　is　almost　zero　when　the　welding　speed　is　2.2　mm/s.　When　the　welding　parameters　are　the　same,　the　porosity　of　the　weld　under　the　intermediate　layer　condition　is　barely　one　third　of　that　in　the　normal　butt　laser　welding　of　brass　sheet.　The　mechanical　properties　of　welded　joint　obtained　at　the　intermediate　layer　condition　is　superior　to　that　of　welded　joint　obtained　at　normal　butt　laser　welding.　Under　the　premise　of　good　weld　formation,　the　effectiveness　of　the　new　method　of　the　copper　intermediate　layer　to　control　the　porosity　defects　of　brass　laser　welding　is　verified.　©　2019,　Chinese　Lasers　Press.　All　right　reserved.