To enable real-time perception of the shape of morphing trailing edge and support closed-loop control of wing profiles, this study focuses on a finger-joint-style variable camber trailing edge. A shape reconstruction method based on fiber Bragg grating (FBG) sensors is proposed. First, an FBG deformation sensor was designed to connect with the trailing edge ribs via supporting components. Using laser tracking and other measurement techniques, the geometry data and key-point coordinates of the trailing edge were recorded at different deflection angles, establishing a mapping relationship between the strain data measured by the FBG sensor and these parameters. The deformation of the trailing edge structure is modeled as a three-joint serial robotic system. By leveraging known dimensional information of the trailing edge, the joint rotation angles are calculated via inverse kinematics using key-point coordinate data. Forward kinematics is then employed to determine the current configuration of the trailing edge, achieving shape reconstruction. The relative error between the reconstruction and the actual trailing edge deflection rotation angle is 1.57%, which confirms the feasibility and accuracy of this approach for real-time shape perception of flexible large deformation wings.