Abstract. Spacecraft in orbit are gradually developing in the direction of large-scale, complex, and distributed. These aircraft structures will undergo complex thermal deformation because of time-varying and distributed thermal excitation in harsh operating environments. Real-time and accurate structural deformation monitoring is important to ensure the spacecraft's performance in orbit. The inverse Finite Element Method (iFEM) is the most promising strain-based deformation reconstruction algorithm for the independent of the material properties and external load information. However, iFEM needs to obtain the strain field of the structure and accurately define the geometry dimension and boundary displacements. For large deployable aerospace structures, the special characteristics of the unfolding mechanism lead to complex boundary constraints, leading to low shape-sensing accuracy of iFEM if characterized inaccurately. This paper proposed a shape-sensing method that combined iFEM with boundary parameters optimization to deal with the limitation. Based on the genetic algorithm, the parameters of boundary constraints in iFEM are optimized to achieve an accurate representation of complex boundary constraints and high-precision deformation reconstruction. The numerical experiment of a sub-panel structure with complex boundary constraints of a deployable Space-borne antenna was carried out to validate the effectiveness of the proposed method.