The electrochemical corrosion resistance properties of nano Fe-Al/Cr3C2 composite coating were tested. The ideal amount of nano Fe-Al/Cr3C2 reunion-granulation particle to be added was determined. Using three-electrode system, the electrochemical corrosion resistance properties of five kinds Fe-Al/Cr3C2 composite coatings were tested. These were micro Fe-Al/Cr3C2 composite coating, nano Fe-Al/Cr3C2 composite coating, and composite coating with additional 5%, 10%, and 15% nano Fe-Al/Cr3C2 reunion-granulation particles, respectively. Zview software was used to fit the AC impedance spectrum in order to analyze the electrochemical corrosion resistance action of coatings. SEM was used to analyze the corrosion surface of coatings. The results indicate that the best electrochemical corrosion resistance property of composite coatings was obtained by adding 5% nano Fe-Al/Cr3C2 reunion-granulation particles. Compared with other coatings, the coating with added 5% nano Fe-Al/Cr3C2 reunion-granulation particles has maximum self-corrosion potential of -0.775 V and minimum self-corrosion current of 0.280 mA/cm2. When the content of nano granulated particles is lower than the optimum value, the electrochemical corrosion resistance properties of coatings are because the content of nano granulated particles is too low to improve density and reduce pore size. When the content of nano granulated particles is higher than the optimum value, the electrochemical corrosion resistance property of coatings are nano granulated particles makes surface of coatings showing high chemical energy.