From the last two decades, the S (1D, 3P) + H2 reactions and its reverse reaction as well as the isotopic variants have received considerable interest because of their important role in combustion and atmospheric chemistry.In present work, the product polarization in the title reaction at collision energies of 10 kcal/mol have been studied by use of quasi-classical trajectory method (QCT) on an accurate 1Apotential energy surfaces to gain insight into the alignment and the orientation of the product molecules.The influences of the isotopic effect on the product vector correlations as well as the reaction mechanism are discussed.