The quasi-classical trajectory calculations O+
+DH (v=0, j=0)→OD+
+H reactions on the RODRIGO potential energy surface have been carried out to study the isotope effect onstereo-dynamics at the collision energies of 1.0, 1.5, 2.0, and 2.5 eV. The distributions of dihedral angle P(φr) and the distributions of P(θr) are discussed. Furthermore, the angular distributions of the product rotational vectors in the form of polar plot in θr and φr are calculated. The differential cross section shows interesting phenomenon that the reaction is dominated by the direct reaction mechanism. Reaction probability and reaction cross section are also calculated. The calculations indicate that the stereo-dynamics properties of the title reactions are sensitive to the collision energy.