Abstract: Through numerical simulation analysis of the boom welding process, the welding deformation was obtained and verified. Based on the simulated deformation, the support was designed, and its effect on deformation was verified by experiments. The results show that the deformation trend of the boom shows the inwards contraction. Peak value of 2.532 mm appears at the free end of weld seam. Simulation results are in good agreement with experimental results, which can meet the requirements of engineering application. It proves accuracy of simulation results. The support is designed in a simple double helix. Welding deformation decreases and is more than 25% with the process support.