The invention discloses a blade surface pitting corrosion resistant coating and preparation method thereof. The coating comprises a bonding layer, a blocking layer, and a surface layer from the inside to the outside, wherein, the bonding layer consists of pure metal Ti, the blocking layer consists of TiN and TiC from the inside to the outside, and the surface layer consists of TiCN. The preparation method is characterized by using an arc ion plating machine to successively depositing the bonding layer, the blocking layer, and the surface layer on the blade matrix. The multi-layer pitting corrosion resistant coating structure disclosed herein has low friction coefficient, high hardness, good wear resistance, good bonding force between the coating and the substrate, and excellent pitting corrosion resistance. According to the invention, in the preparation process, vacuum degree of the furnace body is at least 6.7*10<-3> Pa, the temperature of the furnace body is 250-450 DEG C, so that the marked impact on blade matrix material microstructure in the deposition process can be reduced; by using specific arc current, large particles, liquid drop and cavity on the coating surface in the deposition process can be reduced, so that the coating surface is smooth, compact, and uniform, and the corrosion resistance is improved.