Hard clams are important farmed shellfish in Taiwan. They belong to the phylum Mollusca, class Bivalvia, order Veneroida and family Veneridae. Only depending on the shell morphology is difficult to discriminate them correctly. However, much of the clam classification to date is based on shell characteristics. In order to identify them correctly, we have to work with DNA sequence data. On the other hand, population structure of hard clams is still not very clear in Taiwan. Therefore, the information about the amount of genetic variation within and among population is important for further clams broodstock management and utilization. In this year, we will construct the sequence library of internal transcribed spacer from culturd hard clams by next generation sequencing and analysis the genetics diversity and try to undrstand the intra-species genetics information of M. petechialis and farmed hard clams (Meretrix sp.) from major area in Taiwan.