Hydrogenation of methyl methacrylate (MMA) was investigated over Ru-based catalyst supported onactive carbons (AC), which was prepared by bio-reduction method, using C. Platycladi (CP) leaf extract asreductant. By varying reaction temperature, hydrogen pressure and reaction time, hydrogenation ofMMA over the biosynthesis Ru-based catalyst was carried out, and resulted the optimum conditions,30 C (room temperature), 2.0 MPa, and 50 min. The as-prepared Ru/AC catalyst showed high catalyticactivity towards the hydrogenation of MMA, affording 100% of MMA conversion even under mildconditions without solvent and methyl isobutyrate was the only product.