The controls of oxygen permeation including oxygen delivery to the circumstances without sufficient oxygen supply from the atmosphere are important technologies for chemical and environmental engineering. The combination of the storage of molecular oxygen into the small pore voids and the appropriate discharge to the outside is a promising technique for a new method of oxygen supply. We recently showed that the surface modification of mordenite with organo-disilane compounds blocked the permeation of molecular nitrogen into the micropores. This result suggested that the grafting of the organo-disilane compounds on zeolite surface is also available for controlling oxygen permeations. In this paper, the oxygen storage in the pore void of mordenite was attempted by the modification method under pressurized oxygen atmosphere. A proton type of mordenite with impregnated 1,4-bis(hydroxydimethylsilyl)benzene was heated at 150 °C under pressurized oxygen flow of 10 bar. When this oxygen-filled mordenite sample was heated at 230 °C under argon flow after sufficient deaeration of residual oxygen in dead space, clear decreases of oxygen releasing to the flow were found. A partial oxidation of the organo-disilane compound took place by the oxygen discharged from the micropore, which was supported by the formation of a partially oxidized benzene species of the organo-disilane compound in the treated sample. Although the direct extract of free oxygen was still unsuccessful, this might be the first example that the molecular oxygen is stored in the micropore of mordenite by the effective sealing of the micropore.