In this paper, a static correction method based on a fixed corrector and a lens array is proposed to correct the aberrations introduced by an onboard conformal window in a large scanning field of view. To be specific, first, a fixed corrector is used to correct the static aberrations. Then, a fixed lens array is placed in front of the image plane and the lens units in the array are respectively employed to correct the dynamic aberrations at different scanning angles. Finally, an aberration corrector in an onboard conformal optical system is designed based on the proposed method. The design results show that the proposed method can well correct the aberrations introduced by the conformal window in the scanning field of view of ±42°. Compared with other dynamic or static correction methods, the proposed method can realize the aberration correction of an onboard conformal optical system in a large scanning field of view, reduce the mass of the system, and improve the stability of the system.