The　welding　performance　of　E3,　Er-W,　La-W1and　La-W2　was　investigated　in　this　paper.　The　erosion,　morphological　stability,　U-I　curve　at　high　temperature　and　heavy　current　were　studied　by　direct　current　straight　polarity　tungsten　inert　gas　(DCSP　TIG)　welding.　The　morphology　of　erosion　on　the　electrode　surface　was　explored　by　scanning　electron　microscopy.　The　results　suggest　that　when　the　welding　current　I0　=　250　A,　after　loading　1h　the　mass　loss　of　Er-W　electrode　was　bigger　than　other　electrodes　and　the　tip　size　change　of　Er-W　electrode　was　larger　than　others.　While　the　mass　loss　of　La-W1　was　least　and　the　tip　size　of　La-W1　was　relatively　stable.　The　metallographic　structure　of　the　electrode　tips　showed　that　the　recrystallized　grain　size　of　La-W1　was　much　smaller　than　others,　which　showed　that　metal　rhenium　can　refine　recrystallized　grains　of　material　and　improve　the　electron　emission　performance.　As　a　result,　La-W1　electrode　had　superiority　in　welding　performance.　©　2017　Trans　Tech　Publications,　Switzerland.