The variant aircraft will change the wing structure and skin shape on a large scale when performing different flight tasks. The large-scale deformation reconstruction of the skin multi-dimensional is a difficult point in the research of deformed aircraft. To solve this problem, this article proposes a deformed shape reconstruction method for the deformed aircraft skin based on multi-core optical fiber sensing. Based on the principle of multi-core fiber grating strain sensing, this method uses multiple grating sensing points on the sensor to establish the conversion relationship between grating wavelength drift and curvature, which realizes three-dimensional curve reconstruction. In addition, to reconstruct the shape under the multi-dimensional large-scale deformation of the variable configuration aircraft, this article studies the transformation of the reconstruction curve into the unfolding angle and flip angle of the aircraft wing, and combines the inherent parameters such as the two angles and the length and width of the aircraft wing, and continuously integrates the deformation caused by the change of the two angles by fitting the interpolation, so as to realize the multi-dimensional large-scale deformation reconstruction of flexible skin. Meanwhile, to reduce the error caused by temperature, this article uses the characteristics that the intermediate fiber core of multi-core fiber is not stretched and compressed, and is only affected by temperature, and the center wavelength drift of the intermediate fiber core and the side shaft core is differentiated, so as to realize temperature decoupling. To evaluate the effectiveness of the proposed deformation reconstruction method, the deformation of the aircraft skin under different conditions is experimentally tested, and the deformation reconstruction results are compared with visual measurements. The results show that the average error of multi-dimensional large-scale deformation reconstruction of aircraft skin is 7 mm, and the average error of deformation angle reconstruction is 3. 6% , which can realize multi-dimensional large-scale deformation reconstruction of modified configuration aircraft, and this method has good application prospects in the field of structural deformation monitoring such as aerospace vehicles.