Effect　of　water-cooling　and　air-cooling　condition　on　microstructure　and　properties　of　the　friction　stir　welded　(FSW)　joints　of　5E83　aluminum　alloy　at　rotation　speed　of　400,　800,　1200　r/min　was　investigated　by　means　of　optical　microscope,　scanning　electron　microscope　(SEM),　electron　backscattered　diffraction　(EBSD),　microhardness　test　and　tensile　test.　The　results　show　that　compared　with　air-cooling　condition,　the　flash　of　friction　stir　welded　joints　under　water-cooling　condition　and　the　onion　ring　formation　area　reduce,　while　the　hardness　of　the　weld　nugget　area　is　significantly　improved.　When　the　rotation　speed　is　800　r/min　compared　with　air-cooling,　the　tensile　strength　of　the　joint　under　water-cooling　is　improved,　the　joint　efficiency　is　increased　by　11%,　the　hardness　is　increased　by　11%,　and　the　average　grain　size　of　the　weld　nugget　area　is　reduced　by　43%.　However,　the　fracture　dimples　of　the　joint　under　the　air　cooling　condition　are　large　and　deep,　and　the　plasticity　is　better,　while　the　fracture　dimples　under　the　water-cooling　condition　are　small　and　shallow,　and　the　plasticity　decreases.　©　2022,　Editorial　Office　of　＂Jinshu　Rechuli＂.　All　right　reserved.