To recycle waste materials, this work was focused on development of glass-ceramic from incinerator fly ash with a large content of Cl and its physical property was evaluated. In the process, water washing as a pre-treatment before melting the fly ash was used to remove large amount of Cl component in the ash and to reduce melting temperature. As a result, glass was obtained at below $100^{circ}C$ compared to the melting temperature before washing the ash. Also, internal crystallization occurred under single stage heat treatment (at $850-950^{circ}C$ for 20-340min) without adding other materials into the ash. It was shown that the glass-ceramic was composed of four crystals, diopside, anorthite, akermanite, and unknown phase. Hardness of 8.3GPa was found in the glass-ceramic, which is a high value compared to reported others. Thus, the present process suggests that a good glass-ceramic produced from an incinerator ash could be applicable for structural materials in terms of economic and environmental points.