Observing　that　cracks　appear　simultaneously　on　multi-location　near　weld　on　intracavity　of　domestic　vacuum,　we　investigate　a　series　of　studies　on　welding　residual　stress　and　its　corresponding　elimination　methods.　We　design　seven　types　of　combined-structure　plates　and　quantitatively　measure　the　residual　stress　distribution　by　X-ray　method　based　on　the　characteristics　of　discontinuous　welding　of　different　steel　in　sterilizers.　The　results　show　that　welding　residual　stress　of　all　seven　types　of　boards　reaches　yield　stress　and　causes　the　stress　corrosion　and　corrosion　fatigue　which　are　main　reasons　of　the　intracavity　cracking　of　sterilizers.　In　addition,　residual　stress　resulted　from　carbon　dioxide　welding　is　10%-22%　higher　than　manual　welding,　and　residual　stress　is　indifferent　with　rebar　type.　After　experimental　verification　of　post-welding　watering　quick-cooling　technology　to　eliminate　the　residual　stress,　we　conclude　that　watering　quick-cooling　can　effectively　reduce　the　surface　residual　stress　by　50%-70%　and　increase　fatigue　limit　by　12%-14%　on　watering　surface.　Reducing　welding　residual　stress　is　an　important　way　to　solve　the　problem　of　cracking　in　the　intracavity　of　sterilizers.