As quantity of waste glass powder on the surface of lightweight aggregates increased, absolute dry density increased and water absorption reduced. This reasons are because the amount of coating increases, open pores on the surface of lightweight aggregates become more likely to be closed pores as well as increase to waste glass coating layer relatively reduced pore volume within lightweight aggregates. As sintering temperature of lightweight aggregates increased, absolute dry density reduced and water absorption increased. This reason such as above is because increase of sintering temperature invigorated $CaCO_3$ foaming agent included inner layer. In case of sintering less than $800^{circ}C$ most lightweight aggregates, water absorption had been shown below 4% at 30wt% of waste glass powder and below 3% at 50wt% of waste glass powder. Thus coating of waste glass powder on the surface of lightweight aggregates proved effective in controlling water absorption. In conclusion, we manufactured lightweight aggregate for energy saving, main ingredient is used waste glass of a low softening point(about $700^{circ}C$) and bottom ash containing unburned fixed carbon and volatile matter about 20~25%, which was possible to sinter by decreasing the sintering temperature about 20~30% than existing products. Manufacturing technology of lightweight aggregate has been secured similar water absorption level of natural aggregate, less than 3%, as sintering after coating the external surface with waste glass powder.