The work aims to study the existing forms of Ni in CrNiN coating were studied, and the effects of Ni content on the microstructure, mechanical properties and corrosion resistance of CrNiN coating were clarified. Three kinds of CrNiN coatings with different Ni contents were fabricated by changing the sputter current of NiCr target and keeping constant power of the Cr target using magnetron sputtering technology. The composition, microstructure, mechanical properties and corrosion resistance of the coating are tested and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), focused ion beam microscope (FIB), transmission electron microscope (TEM), nano indentation instrument and electrochemical workstation, respectively. With the increase of NiCr target current from 0.5 A to 1.0 A, the Ni content in CrNiN coating increases from 6.84at.% to 13.36at.%, and the CrNiN coatings has an obvious (200) preferred orientation. The CrNiN coatings are mainly composed of CrN phase, with a small amount of Cr2N phase and Ni metal phase. With the increase of Ni content, the hardness of CrNiN coatings first increases and then decreases. When the Ni content is 8.57at.%, the hardness of CrNiN coatings reaches (16.9±0.7) GPa, which is 36% higher than that of CrN coating, and the toughness and plastic deformation resistance are also improved. The corrosion current density of CrNiN coatings decreases and the corrosion resistance increases. When the Ni content is 13.63at.%, the corrosion potential of the coating is ?0.096 V and the corrosion current density is 5.21×10?9 A/cm2, with the best corrosion resistance. With the increase of Ni content, the compactness of the CrNiN coatings is improved. When the Ni content is about 8at.%, its mechanical properties and corrosion resistance are improved.