This paper aims to analyze the economics in case of using 50% or 100% of coal ashes based on the research about the appropriate recyclable mixing ratio targeting the fly ashes and bottom ashes produced from 10 domestic thermal power plants. Thus, this study is about the economics in case the coal ashes produced from Hadong Thermal Power Plant and Samchonpo Thermal Power Plant are brought into the neighboring Public Water Surface Landfill Site, Galsamyoen Shipbuilding Industry Complex Construction. The results of this study can be summarized as follows. With respect to the economics of coal ashes in the aspect of users, it can save on the cost for selecting borrow pit, purchase of embankment materials and transportation. With respect to Galsamyoen Shipbuilding Industry Complex Construction, it was designed to dredge the total quantity needed for landfill. Thus, in case of both bringing 50% and 100% of coal ashes, the cost for dredging and landfill can be greatly cut and, as a result, competitive price will improve the marketability for end users to move into industrial complex. Also, with respect to the transportation support by power plant, the cost borne by users to transport coal ashes to business site looks enough, but the escalation of transportation cost should be considered in accordance with price fluctuations. With respect to the economics in the aspect of power plants, the cost for the additional construction of ash treatment plant can be saved through shipping out the coal ashes, and this will improve the life cycle of ash treatment plant and meet the government's policies for recycling, as far as I am concerned.