Incineration ash generated from MSW(municipal solid waste) incineration poses hazardous materials included dioxin and heavy metals and causes the secondary environmental contamination problems such as soil or underground water from landfill leachate. Moreover, although the number of operating landfills and available landfill area have decreased, it is very difficult to construct new landfills. due to narrowness of available land apace. Ash melting process is used to reduce the volume and to prevent hazardous trace element from leaching into the soil at landfill sites. But it is known that most of volatile components in ash are not remained in molten slag but vaporize during the melting process. Therefore the physical properties of incineration ash must be understood for developing new melting process.In this study, the plasma technology are applied for ash melting. The result shows that it is able to get stable operation in case of ash feeding and slag discharging, and also the melting slag has no toxic problem and meets the existing landfill quality standard.