Selective hydrogenation of quinolines into 1,2,3,4-tetrahydroquinolines under mild conditions holds tremendous promise for the green synthesis of a multitude of fine chemicals. Herein, we describe nitrogen-doped carbon supported ruthenium nanoparticles were robust for the mide and selective hydrogenation of quinolines to the corresponding 1,2,3,4-tetrahydroquinolines with both excellent activity and selectivity at 30∼50 °C and 10 bar H2.