The excellent activity of platinum-based catalysts in the hydrosilylation of alkenes is limited by their high cost, which has led to the emergence of ruthenium as a cost-effective alternative with promising prospects; however, the relatively low catalytic activity of Ru catalysts remains a major challenge. Herein, a ligand engineering-thermal reduction synergistic (LETRS) strategy was employed to construct single-atom Ru catalysts (Ru-MLDZ_2:1/AC-H₂, where MLDZ denotes N-methylimidazole and AC denotes activated carbon), which demonstrated excellent activity and selectivity for the hydrosilylation of alkenes. Under solvent-free conditions at 60 °C, Ru-MLDZ_2:1/AC-H₂ exhibited comparable catalytic efficiency to platinum-based catalysts, with its alkene conversion rate being approximately 37% higher than that of Ru/AC. Experimental results combined with density functional theory (DFT) calculations demonstrate that the unique coordination environment of Ru-MLDZ_2:1/AC-H₂ exhibits strong affinity toward triethoxysilane, which facilitates efficient Si–H bond activation and reduces the energy barrier in the rate-determining step, consequently leading to significantly enhanced catalytic activity. This study provides a new strategy and valuable insights for designing highly active and economically viable heterogeneous single-atom catalysts.