Abstract: In this study, six coral samples belonging to the genera Porite, Platygyra, Favites, Galaxea, Acroporaand Faviawere sampled from the east coast of Hainan Island. Diversity of coral-associated actinobacteria was investigated using culture-dependent and culture-independent approaches. Specific primers for the phylum Actinobacteria were used to amplify the actinobacterial 16S rRNA gene, and 16S rRNA gene libraries were constructed and sequenced with the Illumina MiSeq platform. The analysis of 16S rRNA gene sequences showed that the actinobacterial sequences were grouped in 37 OTUs on the basis of 97% sequence similarity within one OTU. These OTUs mainly belonged to classes Acidimicrobiales, Corynebacteriales, Micrococcales, Propionibacterialesand Pseudonocardiales. 37.8 % of these OTUs showed less than 97% 16S rRNA gene sequence similarity with validly published species and represented novel taxa. A total of 137 strains were isolated used six different media. As results, they belong to 20 known genera, among them the genera Mycobacterium, Kocuria andMicrococcus were the dominants. The genera Actinomycetospora, Citricoccus and Nesterenkoniawere first isolated from coral hosts. Cumulatively, the east coast of Hainan Island harbors abundant actinobacteria, including large number of unknown actinobacterial groups.