The Blue economy, like the Ocean/Marine economy, refers to the "ocean-based industry," but it includes sustainability. While the ocean/marine economy refers to the ocean-based industry that already has a market, the blue economy values the functions and sustainability of the ocean, including the natural capital that supports it, for which there is no market yet. The Blue Economy is not strictly distinguished from the Ocean/Marine Economy, resulting in an underestimation of the value of the ocean. This paper will clarify the definition of the Blue Economy and its evaluation methodology.