Abstract: In the process of high-speed milling，the release of initial residual stress will cause the machining deformation of aeronautical monolithic component. The machining deformation caused by the initial residual stress release of blank with initial geometric error should be analyzed to control the machining quality，which is very important for the precision machining process.A mechanical model of machining deformation and a finite element method are established to reveal the influence of the initial geometric error of blank on the workpiece deformation. An optimization model of machining position is established with the minimum deformation as the objective. According to the condition that the increment of two adjacent machining positions does not exceed the threshold，a step decreasing algorithm of the optimization model is proposed. The results show that the model calculated values are in good agreement with both the finite element simulated values and the experimental results whether in deformation trend or amplitude. When the blank has initial geometric error or no initial geometric error，the optimal machining positions of the three-frame integral structure are 22.754 3 mm and 23.265 mm，and the corresponding deformation values are -0.006 mm and -0.007 mm，respectively. When the blank has no initial geometric error，its deformation at the position of 22.754 3 mm is 0.043 mm，and when the blank has initial geometric error，its deformation at the position of 23.265 mm is -0.144 mm.It is further verified that the initial geometric error of the blank has a great influence on its deformation.

Key words: aeronauticalmonolithiccomponent, initialresidualstress, initialgeometricerror, machiningdeformation, machiningposition, stepdecreasingalgorithm