Abstract: Theoretical investigations on the stereodynamics of the O(³P)+D₂ reaction have been calcu-lated by means of the quasi-classical trajectory to study the product rotational polarization at collision energy of 104.5 kJ/mol on the potential energy surface of the ground ³A" triplet state. The vector properties including angular momentum alignment distributions and four polarization dependent generalized differential cross-sections of product have been presented. Furthermore, the influence of reagent vibrational excitation on the product vector properties has also been studied. The results indicate that the vector properties are sensitively affected by reagent vibrational excitation.