The Nb-Si-N films were deposited by reactive magnetron sputtering with different N2 partial pressures. The result showed that the composition, microstructure and properties of the Nb-Si-N films depend strongly on the N2 partial pressure. As the N2 partial pressure increasing, the Nb/Si ratio and the surface roughness decease, but the bulk resistance and microhardness of the Nb-Si-N films increase. The microstructure of Nb-Si-N films is a nano-composite structure consisting of nano-sized NbN crystallites and amorphous Si3N4-like compound of Si-N. With the increase of N2 partial pressure, the amorphous tendency of Nb-Si-N films increases and the grain size decreases.