The [PbI6] inorganic framework in the CH3NH3PbI3 could be affected by the oxidization effect of I- ions in atmosphere. The [PbI6] octahedral torsion angle increased similar to 4.94 degrees after the newly prepared CH3NH3PbI3 powders were stored in dry atmosphere for 30 days at 20 degrees C according to the results of XRD Rietveld refinement and X-ray Absorption Fine Structure. Analyses based on density of states indicated that UV vis adsorption edge at similar to 850 cm(-1) corresponded to electron transition from I-5p orbitals to empty Pb-6p orbitals. The increased [PbI6] octahedral torsion angle made the band gap energy of CH3NH3PbI3 increased according to First-principle calculation and UV-vis absorption spectra. As a result, the band gap energy of CH3NH3PbI3 were strongly related to the structure of [PbI6] inorganic framework because the electrons diffused along the [PbI6] octahedral chains in CH3NH3PbI3 perovskite. (C) 2015 Elsevier B.V. All rights reserved.