Abstract: Two kinds of finite element model for analyzing electron beam welding(EBW) stress in titanium alloy plate were set up. For a 4mm thickness plate, the effect of different models on the calculated EBW residual stress was discussed. The results show that there is the longitude tensile residual stress in a very narrow region of welded joint, and the value of the residual tensile stress is close to the yield stress of the titanium alloy. Meanwhile there is the transverse residual compress stress on the surface of the heat-affected zone(HAZ). The residual stress value along the thickness direction is different in the HAZ. So the numerical model for analyzing EBW stress in titanium alloy thin plate should be carefully chosen in practical application.