With　the　development　of　nuclear　power　industry,　the　heavy　section　stainless　steel　vacuum　vessel　presents　many　challenges　to　joining　methods.　The　conventional　welding　processes　can＇t　satisfy　the　strict　accuracy　and　quality　requirements　due　to　its　higher　heat　input.　In　this　paper,　a　3500　W　Slab　CO2　laser　and　a　20　kW　fast　axial　flow　CO2　laser　were　applied　to　weld　austenitic　stainless　steels　with　a　plate　thickness　over　10　mm.　The　autogenous　laser　welding,　narrow　gap　laser　welding　with　filler　wire　and　laser-tungsten　inert　gas　(TIG)　hybrid　welding　with　filler　wire　were　exploited　respectively.　Meanwhile,　the　joint　microstructure　and　properties　were　studied.　The　experimental　results　shown　that　welds　with　good　appearances　and　no　holes　and　cracks　could　be　obtained　with　laser　beam　welding　techniques,　and　the　joint　microstructures　and　properties　are　satisfied　with　the　service　requirements.