Abstract: Ti55 and Ti60 titanium alloy sheets were welded by electron beam, and the influences of parameters on microstructure and mechanical properties of welding joints were studied.The results show that weld zone is characterized by acicular α' martensite plate, and weld center is formed by coarse columnar crystals.Welding parameters can affect microstructure and tensile strength to a certain extent.At room temperature, the tensile strength of joint is higher than that of base metal.At a higher temperature of 600℃, tensile strength of joint is about equal to that of Ti60, and bending strength can be up to 80% of that of base metal, even impact toughness also can be larger than 90% of base metal.Failure occurs in heat-affected zone, and the fracture mode shows toughness characteristic.