The Si/N-DLC films with different Si and N contents were deposited and the corrosion behaviors in the simulated CO2-saturated oilfield produced water was mainly investigated. Results reveal that Si/N-DLC films improves dramatically the corrosion resistance of the substrate. This attributes to not only the channel blockage caused by diffusion of corrosion products, being composed of silicon oxide (SiOx) and metal oxide, but also the stronger support of increased roughness induced by N to the aggregated corrosion products, implying that the Si/N-DLC film are a self-healing protective film. These results provide theoretical guidance to develop the DLC films for anti-corrosive applications.