Abstract: In view of the complex deformation of thin plate caused by TIG bead welding, a thermal-elasto-plastic finite element method was used to establish the prediction model of welding deformation. A non-contact detection method based on digital image correlation technology was proposed to verify the prediction model and a thin plate welding deformation test device was designed. The research shows that the non-contact deformation detection method based on digital image correlation technology can dynamically obtain welding deformation data in the whole field, and can fully verify the welding deformation finite element prediction model. The welding deformation prediction thermo-mechanical coupling model has high accuracy based on Gaussian heat source model, nonlinear transient heat conduction boundary conditions, and material high-temperature performance parameters. The welding deformation of thin plates is saddle-shaped after cooling. Combining the dynamic temperature field and stress field, it is great significance in revealing the mechanism of welding saddle-shaped buckling deformation.