Abstract Vacuum electron beam welding (EBW) was used to weld the thick TA1 titanium alloy sheets. Test results indicated that the coarse serrated-shape α and needle-shape α′ grains were observed in weld zone (WZ); the heat affected zone (HAZ) near the weld center consisted of α and α′ gains; the tensile strength of the TA1 joint was 344 MPa, which was significantly higher than that of the base metal (BM); the fracture of the tensile samples with different penetration depths all occurred on BM, the tensile property of the upper-bottom joint was better than that of the middle joint; moreover, lots of dimples can be observed on the fatigue fracture surface, exhibiting the characterization of the ductile fracture. Highlights • 30 mm thick TA1 titanium alloy sheets were thoroughly melted by vacuum EBW. • Coarse serrated-shape α and needle-shape α′ grains were observed in weld zone. • Maximum tensile strength of vacuum EBW TA1 joint was 344 MPa. • Fracture locations of tensile samples were all occurred on TA1 base metal. [ABSTRACT FROM AUTHOR]