Abstract: The aircraft engine components require high dimensional accuracy, and the position of the core after welding cannot be machined. Therefore, the numerical simulation is used to predict the welding deformation of the rotor assembly. The experiment calculates the inherent strain value based on the theory of thermal elastoplasticity; calculate the inherent strain value of the electron beam welding of GH4169 alloy and analyze the influence of welding parameters on the inherent strain of the welding process; establish the structural model and analyze welding deformation of components under different welding parameters, sequences and fixtures. The result shows that the fourth-stage disc core has the largest axial deformation compared to the first, second and third discs, and the welding deformation can be effectively reduced by increasing the scanning speed and changing the fixtures. Therefore, the welding deformation of rotor assembly can be successfully predicted.