Abstract: Iridium is the most suitable candidate materials for high temperature oxidation resistant coatings over 1 800℃ due to its high melting point and oxidation-resistant property. In this paper, the state of the art for iridium coatings investigation domestic and abroad were reviewed. The main failure mechanism of iridium coating on rhenium substrate was investigated, and feasibility of atomic layer deposition to deposition of compact and stable iridium coatings was analyzed.