Objective To get good crystallization and continuous uniform CuS thin film. Methods The Cus thin film was prepared by the method of electrodeposition, so as to investigate the effect of complexing agent, sulfur sources and copper sulfion ion proportion on electrochemical properties of the plating solution, and analyze the phase composition of thin film in different deposition potential. Results The experimental results showed that sodium citrate was the best complexing agent, while EDTA was the worst. When choosing sodium thiosulfate as the source of sulfur, its reduction potential compared with thiourea would be more positive, oxidation potential would be more negative and the horizontal distance would have smaller values, which was easier to implement codeposition. The ratio of copper sulfide ion to 1 was the most suitable plating condition. When the deposition potential at -0. 8 V, the XRD atlas of thin film appeared the diffraction peaks of cuprous oxide; when the deposition potential at-0. 9 V, Cu₂ S phase generated; when the deposition potential at-0. 9 ~-1. 2 V, the target products CuS was produced, and the diffraction peaks intensity were higher. Conclusion The best depositional conditions are as following: sodium citrate as complexing agent, sodium thiosulfate as a source of sulfur, the ratio of copper and sulfur ion to 1, deposition potential at-1. 2 V.