Abstract: Based on theoretical analysis in LB-VPPA hybrid welding heat source arc shape, “double ellipsoid+3-D conical+cylindrical”heat source model was established for double high energy beam LB-VPPA hybrid welding heat source by secondary development of SYSWELD software heat source model. The temperature fields of LB-VPPA hybrid welding were accurately calculated by the cyclic loading of heat source models with different characteristics of positive and negative polarities in the SYSWELD software. According to the thermal elastoplastic theory, instantaneous evolution of the stress at corresponding node and residual stress distribution after welding were calculated, and the accuracy of numerical simulations was proved by the comparison of the weld cross section of the actual welding experiment and the simulation results and by the actual measurement of residual stress. Comparing the residual stress field of VPPA and LB-VPPA hybrid welding of 5A03 aluminum alloy with 10 mm thickness, it was found that the energy of LB-VPPA composite welding was more concentrated and the high-temperature area was more intensive. Although the maximum longitudinal residual stress was relatively larger, the area of tensile stress was smaller than the VPPA welding. The results of this study were helpful for the research and practical application of aluminum alloy LB-VPPA hybrid welding technology.