Abstract- A 3-D finite element model is presented to study the thermo-mechanical response of thick plate weldments under different multi-pass welding sequences. The Anand’s Viscoplastic Model is applied to simulate the mechanical response of weldments. The thermal modelling of welding zone is also carried by applying the isothermal melting pool approach. In this research the temperature dependency of thermal and mechanical properties of material is considered and the welding parameters such as arc movement, welding speed and welding lag between each sequence are simulated. Finally, in the FE model the addition of filler material into the welded zone is modeled using the Element Rebirth Technique (ERT). The accumulated results show that, on specific point as the number of layers of weld increases, a noticeable change occurs in the magnitude of maximum temperature and its time of reach. For the points near to the weld line, this change affects the amount of distortion, and the through thickness stress components but it has no significant effect on the residual stress components which may arise in the plane of plates.