Abstract: In recent years,municipal solid waste( MSW) removal volume in China has been growing at an annual rate of about 5%,and the disposal capacity of MSW incineration has also been continuously improved. In the process of MSW incineration,fly ash of MSW incineration accounts for about 3% ～ 5% of the total incineration amount. With the continuous improvement of waste incineration treatment capacity,the output of fly ash also increases year by year,and the pressure of fly ash disposal will become more and more severe. As a kind of hazardous waste leached by high heavy metals,fly ash from MSW incineration does great harm to the environment. In this paper,the MSW fly ash composition characteristics and the distribution and properties of heavy metals were discussed. The research progress of fusion treatment technology of municipal solid waste fly ash were expounded from the aspects of fly ash melting process principle,heavy metal conversion characteristics and heavy metal solidification influencing factors,and the effects of the fly ash composition and melting conditions on the melting process and the influence of the curing effect of heavy metals were investigated. Plasma melting technology was introduced,and the effect of melting and solidification of heavy metals was analyzed. At last,some reference suggestions were given for the optimization treatment of fly ash melting and cooling process,and the development direction of fly ash melting technology in the future was pointed out.Heavy metals in fly ash mainly exists in the form of the oxide,chloride,sulfate,melt treatment can change the fly ash composition and phase behavior,resulting in polycrystalline transition and melting phase transformation in the fly ash process.The heavy metal ions are solidified in the silicate Si—O tetrahedral lattice structure by isomorphic substitution reaction,which greatly reduces the leaching toxicity of fly ash and realizes resource utilization of slag. In the melting process,the melting atmosphere,time and the composition of fly ash have great effects on the process characteristics and the migration and transformation of heavy metals,and the different cooling methods will affect the physical properties of vitreous slag. According to the characteristics of melting point and boiling point of heavy metals,some heavy metals with high volatility and low boiling point will be carried in flue gas and secondary fly ash after melting treatment. In the future research,it is necessary to conduct cooling or secondary capture treatment for flue gas and secondary fly ash,and to explore the composition of flue gas. Due to the high energy consumption,high investment and difficult research and development of key equipment in the melting process of fly ash,the melting treatment technology of waste incineration fly ash is still in the technological research and development stage in China,and there is no stable chemical industry operation example. But there have been some pilot studies. Before melting treatment,the composition of fly ash should be analyzed and pretreated according to the composition of fly ash. By adding fluxing agent and adjusting the basicity of fly ash,the melting treatment of fly ash is carried out to reduce the energy consumption of melting treatment and treat heavy metals efficiently and stably. On the basis of the stable and effective test in the laboratory,the technology improvement and innovation of the plasma melting treatment device can be carried out to improve the stability of the plasma flame,realize the efficient separation of molten slag and enhance the durability of the device.