Abstract: Weld configuration of TA12 titanium alloy is very good for electron beam welding(EBW).The main microstructure of weld is martensite, and the tiny rare earth rich phases is dispersedly distributed in the weld zone, and dimension whose configuration changes disciplinary along the joint.By hole drilling method measuring weld residual stresses, the results show that longitudinal stresses are higher than transverse stress, which present gradient distribution along the vertical direction of the weld.In the weld all the longitudinal residual stresses are tensile stresses, and whose peak stresses are lower than yield stresses, while the transverse stresses are very low pressure stresses.Along the weld direction in the central of the plate the residual stresses distributing are approximate equal.