The atomic oxygen-induced surface reaction has been studied on the D/Si(100) surfaces. The mass spectroscopic method reveals that D-2 desorption as well as D2O formation are induced upon collision of oxygen atoms with the D/Si(100) surfaces. As the oxygen atoms are taken into the Si-Si bonds, the desorption of D-2 and D2O molecules is terminated despite the survival of the D adatoms. We propose a possible mechanism of the oxygen-induced D2O formation and D-2 desorption.