Electrochemical impedance spectroscopy（EIS）occupies an important positionin the evaluation of protective performance of organic coating. After nearly half a century ofresearch and application，many experimental，data processing and evaluation methods for EIS have been derived. In this paper，some major research and application works on EIS for the evaluation of protective performance of organic coating had been reviewed，and some shortcomings of EIS in practical applications had also been elaborated. Especially，EIS could not be used for evaluating the cathodic protection or activity inhibition coating alone，and earlystage tests by other methods should be conducted to support the EIS interpretation. Finally，it was proposed that the judgment basis of EIS for coating aging and protection evaluation remained in the empirical stage. In order to improve the universality of EIS，it was urgently needed to establish the relevant databases，which could be used for data management and sharing，supporting the rapid coating evaluation，and helping the long-term protection of steel structures.