Abstract: Electrostatic precipitator（ESP） ash and bag filter（BF） ash from a circulating fluidized bed（CFB）municipal solid waste（MSW） incineration power plant in Zhejiang Province were sampled as the research objects.Particle size distribution, surface characteristics, mineral composition, heavy metal loading, and leaching characteristics of ESP ash and BF ash were systematically studied. Results show that: 1) the particle size distribution of ESP ash and BF ash displayed unimodal distribution, which were mainly distributed in the range of 9.8～120.6mm and 3.8～78.8mm,respectively; 2) the fly ash particles had negligible porosity and the adsorption of heavy metals mainly took place on the exposed surface of ESP ash and BF ash; 3) the main mineral composition of ESP ash was SiO₂, whereas BF ash primarily consisted of SiO₂, Ca（OH）₂, CaCO₃, NaCl, and KCl; 4) Cd and Hg were transferred into fly ash by evaporation, condensation and adsorption, whereas Se was transferred into fly ash by chemical adsorption; As and Cr were transferred into the fly ash mainly by entrainment, whereas Pb, Cu, and Zn were transported into the fly ash mainly in the form of chloride by evaporation condensation and adsorption; 5) Cd, Cu and Zn in fly ash showed high leachability, while the leaching rates of Cr,Hg and Se were relatively low.