The adsorptions of nitrogen atoms on Ru(0001), (10(1-)0) low index surfaces and (11(2-)0), (11(2-)1) stepped surfaces were investigated by the five-parameter Morse potential(5-MP) method in details. Calculated results demonstrate that N atoms show a tendency to be adsorbed at threefold sites. No subsurface state was found for N atoms on Ru(10(2-)0) surface. There exist 6 stable adsorption sites for N atoms on Ru(11(2-)1) stepped surface which can be classified into 3 types: the on-surface adsorption state, the facet adsorption state and the subsurface state. Moreover, two new perpendicular vibrations at 97 and 98 meV are predicted. All calculated results are in good accord with HR-EELS experiments.