Ocean Thermal Energy Conversion (OTEC) demonstration plant in Okinawa prefecture deep seawater research center (OPDSRC) in Kumejima, Japan has started the operation for 2 years ago by Okinawa prefecture. Where, the maximum 13,000 t/day of the deep ocean water (DOW) is pumped up from a depth of 612m, which is the largest flow rate in Japan. The utilization of DOW has been expanded as one of the biggest industry and employment generation in Kumejima-island after for 10 years of the operation. For further development, the confirmed seawater data such as temperature, salinity and ions…etc. is required as well as the expansion of the seawater intake facilities. However, there are few available seawater sampling data at the coast of Kumejima-island. Moreover, for OTEC, although the biofouling of heat exchangers especially for the evaporator using surface seawater is the one of the critical issue for the performance of the power plant, the heat exchangers in OPDSRC has a 10 years of long operation without cleaning and/or maintenances. Hence, the paper describes about the analysis results of sampled seawater at the coast of OPDSRC for the design of OTEC and for other multi-purpose utilization of DOW with the cooperation of the training ship of National fisheries university “Koyomaru”. Furthermore, the sampled surface and deep seawaters drawn at OPDSRC are analyzed to confirm the composition of the Nutrients and the elements concentration.