The modification of some rare earth metal cations to polymer-stabilized Pt colloidal clusters leads to significant increase in both the ee and the activity in the homogeneous enantioselective hydrogenation of methyl pyruvate to (R)-(+)-methyl lactate. Compared to ee (72.5%) in the absence of rare earth cations, the highest ee (88.0%) in ethanol solvent is obtained by adding a suitable amount of Yb3+ into the Pt colloidal cluster catalyst. The modification effect of rare earth cations is also effective in other alcohol and water solvents.