[en] Highlights: • The out-of-plane deformation in Ti₂AlNb alloy joints produced by electron beam welding show a concave-concave mode. • The weld shape varies significantly according to the focus current of the electron beam, and has four kinds of shapes. • The joint with a nail-shaped weld bead has the least angular distortion when the heat input is kept constant. Ti₂AlNb alloy is an attractive material for advanced aerospace applications. Welding of the alloy can lead to severe distortion, influencing dimensional precision of the welded workpiece and structural integration. In this study, the effect of welding parameters on the weld shape of the Ti2AlNb alloy jointed by electron beam welding was investigated. A three-dimensional thermal-elastic-plastic finite element method was developed to simulate the welding distortion. The simulation results agreed with experimental measurements very well. It showed that the developed computational approach has sufficient accuracy and can be used to predict welding distortion. Because of the low longitudinal shrinkage force, the workpiece was bent to a concave-concave shape. When welding without fixture, the bead-on-plate joint has less distortion than butt weld. Also, it was found that focus current can significantly change the weld shape, resulting in various of transverse shrinkage distributions, consequently determining transverse bending deformation. When welding heat input is kept constant, the nail-shaped weld made with a certain negative defocusing electron beam will have minimum angular distortion.