As　the　top-down　management　on　the　radioactive　element　Th,　its　price　became　more　expensive,　which　promoted　the　development　of　environment-friendly　electrodes　to　replace　Th-W.　The　welding　performance　of　Th-W,　Ce-W,　(La-Ce-Y)-W　and　E3　electrodes　widely　used　in　US　was　investigated.　The　erosion,　morphological　stability　and　U-I　curve　at　high　temperature　and　heavy　current　were　considered　by　direct　current　straight　polarity　tungsten　inert　gas　welding　(DCSP　TIG)　welding.　The　morphology　of　erosion　on　the　electrode　surface　was　explored　by　scanning　electron　microscopy　(SEM),　and　energy-dispersive　X-ray　spectrometer(EDX)　was　used　to　study　the　distribution　of　oxide　additions　on　electrode　tip.　The　results　suggested　that　when　the　welding　current　I0=200　A,　after　loading　5　h,　the　property　of　anti-erosion　of　E3　and　WX　electrodes　was　superior　to　that　of　Th-W　and　Ce-W　and　the　mass　loss　was　approximately　linear　with　time　with　fine　thermal　stability.　The　metallographic　structure　of　the　electrode　tips　showed　that　the　recrystallized　grain　sizes　of　E3　and　WX　were　much　smaller　than　those　of　Th-W　and　Ce-W,　which　was　largely　due　to　the　lower　working　temperature　and　suggested　a　better　electron　emission　ability.　The　behavior　of　rare　earth　oxides　on　the　electrode　tip　revealed　the　nature　of　the　difference　in　working　performances.　CeO2,　which　had　the　highest　diffusion　rate,　had　a　magical　effect　during　low　current　welding　and　arcing;　Y2O3　and　La2O3,　which　had　a　higher　thermal　stability,　diffused　slowly　unless　the　temperature　elevated　to　higher　degree.　So,　they　played　an　important　role　in　the　condition　of　heavy　current　long　time　welding.　Owing　to　the　synergy　of　three　rare　earth　elements,　the　work　function　of　the　electrode　decreased　significantly,　the　electron　emission　process　became　more　stable.　As　a　result,　the　ternary　rare　earth　tungsten　electrodes　(WX)　had　superiority　in　welding　performances.　©,　2014,　Editorial　Office　of　Chinese　Journal　of　Rare　Metals.　All　right　reserved.