Abstract: To solve the problem of low efficiency in simulation of multi-pass welding of thin plate by finite element method, a new method, which substitutes routine 3D solid element modeling with laminated shell element modeling based on the theory of thinshell and composite layer, was used to thermo-mechanically simulate the single or multi-pass welding of thin plate and to predict the residual stress.For the laminated shell element, the shell section points with changeable material properties were used to describe the thickness of plate.A classic analytical model was used to solve the transient temperature distribution and then ABAQUS linking some extended user subroutine was used to analyze the stress.By comparing the residual stress obtained from this method with that based on the solid-element method, the simulation efficiency of this method is higher and the precision is equivalent to that of the solid element method.