Abstract: Thermo-mechanical parameters related with temperature were used to compare qualitative influence of the Young's modulus,coefficient of thermal expansion on the welding residual stress.The result shows that the rise of Young's modulus can increase the welding residual stress and make the peak value of longitudinal residual stress transfer to a single hump from a double one;the decline of thermal expansion coefficient may result in the falling of the welding residual stress and lessening the difference between wave crest and wave trough;the peak value of longitudinal residual stress drops with the increment of Poisson ratio.The longitudinal welding residual stress of aluminum alloy is lower than its yield limit and appears double hump effect near the weld,that is the results of the thermo-mechanical parameters influence.The simulation results of welding longitudinal residual stress are testified using cutting pieces stress relieving method with the flat plates of 2024-T4 aluminum alloy.The simulation results are well accordant with test,which prove the validity of the simulation results.