In order to solve the problem that it is difficult to correct the complex aberration introduced by conformal light windows in large aperture and large field-of-view systems, a new method is proposed for the design of airborne optical systems. This method adopts the inner surface of light windows and the discrete reflective mirror for aberration correction, balances the aberration through sub-aperture correction strategy, and gives a control algorithm that matches with the discrete reflective mirror to solve the problem of wave surface inconsistency between sub-apertures, which has the advantages of high degree of freedom and simple structure. The simulation experiments verify that the method can correct the wave aberration RMS of the central field of view from 0. 62λ to 0. 06λ(λ=950 nm) at 120 mm aperture and 0°～30° scanning angles. The research shows that the discrete reflective mirror has good performance in dynamic aberration compensation, and the proposed correction method has wide application potential in the design of conformal optical systems.