A theoretical method is developed to predict the bending modulus of hollow integrated sandwich composites in the warp direction. The pure bending moment is deduced by the sandwich beam theories when the face-sheet is responsible for the total moment proportion. On this basis, the relationship between the total bending modulus and the bending modulus of the face-sheet is established. Therefore, the bending modulus of the material is predicted by calculating the modulus of the face-sheet and combining the corresponding structural parameters, and the influence of various woven parameters on the bending modulus is also examined and analyzed. In the end, the accuracy of the theoretical prediction method is verified by comparing the theoretical predictions and the experimental data.