Abstract: It is difficult to guarantee the uniformity and batch-to-batch consistency of the initial residual stress of large components, which will cause many problems such as high distortion, high uncertainty, and unstable contour distortion process of components. The paper presents an optimization method for the equilibrium and determinism of initial residual stress based on blank selection. A mechanical model of ‘stress-structure-distortion’ was constructed. Full-scale stress condition number and local stress condition number in the stress input module were extracted, which can be used to evaluate the equilibrium and determinism of complex initial residual stress. The influence law of stress condition number on machining distortion was studied. Furthermore, the method of blank selection and workpiece position selection based on stress condition number was proposed, which can be used to select optimal blank. An aviation single-sided stringer component was taken to carry out the verification test. The results showed that optimal workpiece position were 4 mm (65 mm-thick blank) and 7 mm (70 mm-thick blank) respectively and optimal blank thickness was 70 mm.