Abstract: In the welding deformation prediction of large-scale structures based on inherent deformation, the inherent deformation database of welded joints is indispensable. According to the characteristics of welded joints, the establishment method of the inherent deformation database based on XGBoost algorithm was studied. The structure of the inherent deformation database was designed on the basis of the inherent deformation factors of welded joints; the grid search method was adopted to determine the optimal hyper parameters and the inherent deformation prediction model was built. A simple example was used to verify the application of the proposed database establishment and improvement method in engineering practice. The research results are of great significance to mining large data of welding deformation at the production site and precisely predicting the deformation of welded structure.