Abstract: The welding experiment on 30 mm thick Q690 steel plate in full-scale top beam structure of hydraulic support was carried out.The welding deformation of a relatively small structure selected from the top beam structure was firstly simulated with the thermal-elastic-plastic finite element method based on the efficient heat source model,and then the inherent strain was obtained from the small model,finally the acquired inherent strain was input into the full-scale shell element model of the hydraulic beam support structure to calculate the welding distortion deformation.The results show that,the proposed method can predict the welding deformations of large structures efficiently and accurately,the computational welding deformations of the top beam structure agree well with the experimental results; the angular distortion deformation is the main deformation of the top beam structure,which is not uniform on both sides.