The present study is to perform a research for recycling the ponded coal ash as construction materials that increases every year at thermal power plants. It is thought that when ponded coal ash is recycled, it would be environment-friendly and be helpful for national economic development. accordingly, Mechanical properties of foamed light-weight CLSM which is made from mixture of ponded ash, fly ash, cement, a foaming agent and water was investigated, and suggested its applicability. It was revealed that these properties are satisfied with the criteria of mechanical properties, so there would be no problem in recycling as construction materials. The utilization of ponded ash being currently risen as an serious issue can be maximized, and it is expected that thermal power generation, which is a basis of the domestic energy industry, can be carried out smoothly by consuming the ponded amount of coal ash which is a byproduct according to thermal energy generation.