The composite materials with vacuole inclusions are modeled by meshing matrix materials into entity units and inclusions into thin-shell units. The element stiffness of the smooth closed thin-wall in plain-strain condition is formulated by Kirchhoff-Love theory. And corresponding to the model, the multi-point constraint conditions of the material interface are obtained. A representative volume of composite materials with vacuoles inclusion is taken for example; the effective modulus variance during the interfacial debonding procedure is simulated. The result shows that the meshing scheme and the assembling scheme proposed are valid and the number of freedoms is reduced.