The work aims to compare the corrosion resistance performance of Cr/CrN/CrAlN coating and Cr/CrN alternating coating. Electrochemical polarization curve, impedance spectrum and neutral salt spray test were used to analyze the difference in corrosion resistance of the two coatings by characterizing the microstructure with micro-morphology of scanning electron microscope (SEM) and atomic force microscopy (AFM). The effect of pre-scratching on the corrosion resistance of the coating was investigated to simulate the damage conditions of coatings during service. The self-corrosion current density of the Cr/CrN/CrAlN coating was 2 orders lower than that of the Cr/CrN alternating coating and the TC4 substrate and the corrosion rate was reduced. The polarization resistance Rp of the non-damaged Cr/CrN/CrAlN coating was 868.7 kΩ?cm2, and that of coating with a scratch remained 792.0 kΩ?cm2. However, the resistance Rp of the coating with 5 scratches was 77.2 kΩ?cm2, which is reduced to about 8% of that in the original coating. After 288 h continuous salt spray corrosion, the weight gain per unit area of Cr/CrN/CrAlN coating was only 0.1 mg/cm2, which was much smaller than that of Cr/CrN alternating coating and TC4 substrate, and the weight gain curve tended to become flat. The corrosion weight gain rate of the Cr/CrN coating increased significantly after continuous salt spray corrosion for 24 h, and the slope of the weight gain curve increased obviously. The Cr/CrN/CrAlN coating increases the interface clogging of microcracks and dislocation motion, which avoids the connection of the pores and prevents corrosion medium from entering the substrate, so the corrosion resistance is improved. For Cr/CrN/CrAlN coating with pre-scratched surface, local corrosion of the coating firstly occurs. After acceleration by cathodic polarization, the corrosion pit extends to the interface of coating/substrate, which exacerbates the partial peeling of the coating.