Abstract: The microstructure and mechanical properties of ZTC4 titanium alloy joints welded by electron beam were investigated by room-temperature tensile test, microhardness test and metallographic examination. The results showed that the microhardness of welding seam was higher than that of the base material. The microstructure of welding seam was the mixed pattern of acicular α phase with β phase, which grain size was finer than base material that exhibited a coarse α plate colony structure composed of prior β grains. The welding joints with good performance of ZTC4 alloy may be obtained by means of electron beam welding and the tensile strength of welding seam is similar to the base material. Selecting the appropriate base material and heating treatment system may improve the stability quality of welding joints and decrease the dispersion of the properties data.