We report a simple method to synthesize Ru nanoparticles confined in the nanochannels of OMAS (Ru@OMAS). This method eliminates laborious multi-processes that are typically required for pore confinement of metal nanoparticles. We prepare three types of Ru@OMAS with different Si/Al mole ratio (denoted as Si/Al-x, x = 10, 30, 50) having the same large pore size (~30 nm) and Ru NP loading (3 wt. %). Changing Si/Al ratio strongly affects the number/strength of acid sites and the metal-support interaction, thereby mediating the catalytic acitivity and product selectivity. With increasing Al content (decreasing Si/Al ratio), support’s acidity, metal-support interaction, and dispersity of Ru particles increase, whereas reducibility of Ru decreases significantly.