Abstract: The morphology of welded joint between Ti-43Al-9V-0.3Y and TC4, the phase composition and the effect of the welding parameters on the tensile-strength are analysed.The weld zone is mainly composed of the coarse columnar crystals, and its phase composition includes Ti₃Al, TiAl, B2 and YAl₂.The columnar crystals in the weld near TC4 are grown up from the grains of the base metal, and the equiaxed grains in the heat-affected zone are coarse α+β structure, and the sizes of the two kinds of grains are distinct.The weld near TiAl is a corrosion resisting bleached zone, and it is composed of single B2 phase.The effect of the welding parameters on the tensile strength of the joint was analyzed.The results shows the welding speed has little influence on the tensile strength, a peak of the tensile strength appears with the change of seam current. the maximum of the tensile strength of the weld is 209.8 MPa in the tested range.