The control of welding distortion during assembling process is very important. Using numerical simulation methods to obtain the welding distortion is an effective way to control the quality of welding. At first, taking the bead-on-plate welding as an example, the predictions of welding distortion were made using the shrinkage force method and the thermo-elastic-plastic method for comparison. It was concluded from the comparison that the simulation results by using the two methods are consistent. Therefore, the shrinkage force method can be applied to prediction of structural welding distortion in engineering. Based on the theory of welding shrinking force, welding deformation was predicted for the bogie side frame of railway vehicle. According to all the deformation results from the finite element analysis, the welding deformation of the bogie side frame was lager than the tolerance of quality and in reasonable agreement with the experimentally determined distortion values from literature. The work in this paper indicated that the shrinkage force method was effective to predict the welding deformation and to control the welding quality in large complex structures, such as the bogie frame of railway vehicle.