Iridium (Ir) is one of the most potential oxidation-resistant and thermal shock-resistant materials for carbon/carbon composites above 1800 oC in aerospace field. In this work, the current status of research of Ir coatings is reviewed. The main preparation methods, physical vapor deposition, metalorganic chemical vapor deposition, melting salt electroformed deposition and double-glow plasma deposition for the oxidation-resistant and thermal shock-resistant Ir coatings, are introduced. The interlayer between Ir coating and carbon/carbon composites which can increase bonding strength and match thermal stress is studied. The summary of engine test of Ir coatings is presented. The influencing factors of service time of Ir coatings are discussed. The practical techniques to prepare Ir coatings in China are put forward.