Aircraft skin has large size and thin wall thickness,which is prone to machining deformation,and there is a complex coupling relationship between cutting force and machining deformation,so it is difficult to achieve good prediction effect by ordinary non iterative machining deformation prediction method.Aiming at the deformation phenomenon of aircraft skin mirror machining,based on the establishment of the cutting force model of customized tool for mirror milling,an iterative prediction method of machining deformation was proposed.The problem of complex coupling between cutting force and machining deformation can be solved by the method,and the effectiveness of the method was proved by simulation and experiment.Compared with the ordinary non iterative method,the method can predict the deformation trend and amplitude more in line with the actual aircraft skin mirror machining,the difference between the simulation predicted value and the actual machining deformation is more stable,the prediction error is smaller,and it can predict the deformation of the skin mirror machining more accurately and effectively.