Three electron beam welding processes were used to obtain the welded joints of Ti6242 titanium alloy. The microstructure and mechanical properties of electron beam welded joints of Ti6242 titanium alloy were studied by means of microstructure analysis, tensile and impact property tests, fractography analysis and so on. Results show that the electron beam welded joint of Ti6242 titanium alloy consists of base metal zone, heat affected zone and weld fusion zone. The heat affected zone can be divided into equiaxed grains area, incomplete–β area and nearly complete–β area. The microstructure of the weld fusion zone is composed of β–columnar grains with a small amount of β–equiaxed grains distributing in the center. The acicular martensite α′ phase was found both in the weld fusion zone and heat affected zone. With reasonable control of welding heat input, Ti6242 titanium alloy can obtain favorable welded joints with higher strength, slightly lower plasticity and lower impact property than the base metal. The tensile fractography shows dimple morphology and its fracture mechanism is micropore aggregation plastic fracture. The impact fractography is characterized by a mixture of dimples and quasi-cleavage, simultaneously many small dimples and tearing edges distribute between the columnar fracture surfaces. The fracture mechanism is a mixture of micropore aggregated fracture at the dimple and slip band fracture on the quasi-cleavage plane.