Abstract: Based on ABAQUS software, a thermal-elastic-plastic finite element method (FEM) was developed to simulate welding temperature field, residual stresses and deformation for multi-pass joints. The residual stresses and deformation in Q345 butt-welded joint with 16 mm thickness were simulated through using the developed computational approach. Meanwhile, experiments were carried out to measure the welding residual stresses and angular distortion in the butt-welded joint. Through comparing the measured data and the simulated result, it is found that both the residual stress and deformation predicted by FEM are in good agreement with the experimental results. In addition, the results show that the angular distortion and transverse shrinkage increase with the number of weld pass. The numerical results also suggest that the region with high tensile longitudinal stress slightly decreases when the number of weld pass changes from three to five, while the peak value of longitudinal residual stress is not sensitive to the number of weld pass.