The stereodynamics in the chemical reaction O+ +H2and its isotopic variants at a collision energy of 20 kcal /mol are investigated by using the quasi-classical trajectory (QCT) method on RODRIGO surface. The correlated k- j', k-k'-j' angular distributions, polarization-dependent differential cross sections (PDDCSs) and the product rotational alignment are discussed in detail. The calculations indicate that the stereodynamic properties of the reactions of O+ +H2→OH+ +H、O+ +DH→OD+ +H and O+ +TH→OT++H are sensitive to the mass factor and the repulsive energy of diatomic molecule.