Abstract: In order to reveal the deformation coordination mechanism of the composite spherical array sandwich structure from the view of structural mechanics, the indentation mechanical model of the typical local plate lattice for the structure was established under a concentrated load.For a rectangular plate with elastic support of four points and equal moment constraints of four edges, the elastic bending deflection under a concentrated load was treated as the superposition of deflections under two cases, a concentrated load with elastic support of four points and free boundary of four edge sadded to equal moments along four edges. The former was further decomposed into the deflection of rigid plate with elastic support of four points and elastic plate with rigid support of four points and free boundary of four edges under the same concentrated load.The latter was also further decomposed into the deflection of the elastic plate with equal moments along two opposite edges and along the other two opposite edges with the same simply supported boundary. The analytical solutions of three plates with different spans and concentrated force positions were compared with finite element method results, demonstrating the accuracy of the proposed solution. Results show that the mechanical model effectively can effectively reveal the bending deformation mechanism and guide the parametric design of the composite spherical array sandwich structure.