Abstract: The high temperature properties and microstructure of GH3230 alloy argon arc welded joint were investigated by SEM, high temperature tensile test and high temperature creep test. The results indicate that the equiaxial dendritic microstructure of welded seam was made up of equilibrium frozen Ni based solid solution, γ-FeCrNiC, a little bit granular carbides, γ′-Ni3Al and MC.The microstructure in heat affected zone was the same as in the base metal, but grains in heat affected zone was bigger than in the base metal. The joint exhibited good high temperature properties with a tensile strength of 244 MPa at 927 ℃, as same as the base metal, and a creep life of 38.82 h at 927 ℃ and 62 MPa which was higher than the base metal. The fracture morphology of welded joints after high temperature tensile test and creep test were basically identical which were dimple and intergranular fracture, respectively.