[Objective] The aim of this study was to uncover the diversity of actinobacteria associated with corals Porites lutea and Galaxea fascicularis. [Methods] Total DNA of coral samples was extracted for PCR amplification with the primers of class actinobacteria. Two clone libraries were constructed for P. lutea and G. fascicularis coral samples. We carried out phylogenetic and statistic analysis based on 16S rRNA gene sequences in order to investigate the communities of actinobacteria associated with corals P. lutea and G. fascicularis. [Results] One hundred and eighteen clones of the P. lutea library were sequenced. They were classified into 58 OTUs, which distributed in suborders Acidimicrobineae, Corynebacterineae, Micrococcineae, Propionibacterineae and unclassified groups. Ninety-six clone sequences were retrieved from G. fascicularis library. They were classified into 31 OTUs, which were distributed in Acidimicrobineae and unclassified groups. Results of diversity index and rarefaction curve analysis suggested that coral P. lutea harbored more diverse actinobacteria than G. fascicularis. [Conclusion] Actinobacteria associated with corals P. lutea and G. fascicularis showed a high level of diversity. There were a large number of unknown Actinobacteria taxa in this environment.