Diamond–like carbon (DLC), which used to describe a wide range of amorphous carbon films containing sp³ bond, has been extensively studied and applied in the fields of mechanics, electronics, optics and medicine, due to their excellent properties, such as high hardness and wear resistance, low friction coefficient, high chemical inertness, low expansion coefficient, well biocompatibility, and so on. However, high internal stress and low thermal stability are the main problems in applications of DLC. On the one hand, high internal stress is generated in the growth process of DLC, which greatly reduces the adhesion strength of the film to substrate, making the film easily delaminate from the substrate. On the other hand, the DLC will graphitize and be obviously oxidized when the temperature is over 350 ℃, leading to the deterioration of properties evidently. Non–metal N has strong affinity with transition metal Cr and their compound CrN has high hardness and oxidation resistance. So it is expected that composite film with hard CrN crystalline phase imbedded within DLC amorphous matrix maybe obtained by doping N and Cr simultaneously. In this paper, the uniform, smooth and dense C–N–Cr films with different compositions were deposited on cemented carbide substrate at different nitrogen flow rates by pulsed bias arc ion plating. The surface morphology, composition, structure and properties of C–N–Cr films were investigated by SEM, GIXRD, XPS, Raman spectra and Nano–indentation, respectively. The results show that the nitrogen content in the C–N–Cr films increases linearly and then slowly with nitrogen flow rate increasing, while the Cr content first keeps stable and then decreases linearly. The C–N–Cr films have high hardness (>30 GPa) and elastic modulus (>500 GPa) when the nitrogen flow rate is not more than 20 mL/min, above which the hardness and elastic modulus decrease drastically and only have the value of 13.6 and 190.8 GPa when the nitrogen flow rate is 100 mL/min.