Abstract: Golden calcareous coral was discovered in latest decade.It was unknown by people due to the low output. Its iridescence on the surface makes it very different from the common red calcareous coral，golden horny coral and black coral.Optical microscope，scanning electron microscope with micro X－ray spectrometer and LA－ICP－MS are applied in the research on the structure of the golden calcareous coral.Research reveals that it consists of the interlayers of aragonite layers and organic layers，and the single aragonite layer consists of micro-nanometer grains.Such combination of organic and inorganic nanometer material results in the special iridescence effect on the surface of golden calcareous coral.