In order to prepare nitrogen-containing copper alloy films with stable structure and performance, and then improve the hardness of copper alloys, the relatively large negative mixing enthalpy between Nb and N and the effect of Ni were utilized to bring N into Cu to achieve the purpose of stable existence of N, which based on previous research of the stable solid solution cluster model in the composition design of Cu-Ni-based copper alloys. Cu-Ni-Nb-N quaternary alloy thin films and reference samples were prepared by magnetron sputtering on Si (100) substrates in an atmosphere where the N2/Ar ratio was 1/30. Then the composition, structure and film-substrate interface of films were analyzed by EPMA, XRD and TEM, respectively, and the resistivity and hardness was measured by double-electric four-probe instrument and super-light-load Nodule hardness tester. Compared with Cu(N) films, quaternary alloy films exhibit better structural stability and higher hardness. The as-deposited quaternary thin films are composed of nanoscale columnar crystals of copper and a small amount of NbN, and their hardness values are about 5 GPa. After annealing at 550 ℃ for 1 h, the films show good densification, part of N can exist stably in the form of NbN compound, the hardness of most of the films is above 3 GPa, simultaneously, these films exhibit good conductivity. Therefore, the stable solid solution cluster model can be used to select the nitrogen fixation elements, and the nitrogen-containing copper alloy films with good comprehensive performance can be prepared, which lays a foundation for their further application in the surface modification of copper and its alloys.