Abstract: The corrosion of AF1410 steel samples only coated by a layer of H06-076 epoxy primer was studied by the electrochemical impedance spectrum (EIS) technology. Accelerated environmental spectrums were applied in the test. The results showed that the anti-corrosion of AF1410 only coated by a layer of H06-076 epoxy primer was pretty weak, especially when the coating was coated badly at the corner. Water was easy to get into the interface and the corrosion of basic metal took place. The corrosion behavior of metal coated by organic coatings can be early characterized by EIS method, and the protection performance of coatings can be also assessed by EIS method. The trend of 10 Hz phase was in accordance with that of the |Z| 0.1 Hz measured by EIS.