A theoretical analysis is conducted on the deformations of the Miura-ori patterned sheet. The sheet deforms within the elastic range of the material Elvaloy in the mechanical tests, which includes the out-of-plane compression, in-plane compression and three-point-bending tests. Among other assumptions, the Miura-ori’s one degree-of-freedom mobility and rigid facets are kept in the theoretical model for the simplicity of the analysis. The global deformations of the patterned sheet are integrated by the elastically deformed portions along the ridgelines. The relationships between reaction forces and displacements are obtained using the principle of virtual work. In energy balance equations, external works are done by reaction forces and internal works are generated by elastic deformations along ridgelines. The theoretical results show good correlation with the experimental data, except in the in-plane X1 compression and three-point-bending X1. The disparities between the theoretical and experimental data indicate a refined model is needed for a better description of the corresponding deformations.