The mechanochemical treatment of fly ash generated from a medical waste incinerator was subjected to grinding for 2 hr at 400 r/min in a planetary ball mill.The treated fly ash was characterized by a suite of analytical methods including High Resolution Gas Chromatograph/High Resolution Mass Spectrometer,Mastersizer 2000 Particle Size Analyzer,QUADRASORBTM SI Surface Area Analyzer,Scanning Electron Microscopy and X-ray diffraction.Results showed that abatement effciency of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans(PCDDs/Fs) in terms of total concentration averagely amount to 76%which was relatively higher than that of I-TEQ concentration averagely amount to 56%;the most concentration of toxic congeners as well as isomers of PCDDs/Fs decreased after mechanochemical treatment.The treated fly ash was characterized by a more homogeneous distribution of concaves as well as the significant decreasing in overall particle size and great enlargement in surface area.The major crystallization phases or intensities were considerably changed by mechanochemical treatment,of which a new phase containing chlorine formed may be a possible factor suggesting chlorination reaction occurring on the crystalline surface. The mechanochemical treatment of fly ash generated from a medical waste incinerator was subjected to grinding for 2 hr at 400 r / min in a planetary ball mill. The treated fly ash was characterized by a suite of analytical methods including High Resolution Gas Chromatograph / High Resolution Mass Spectrometer, Mastersizer 2000 Particle Size Analyzer, QUADRASORBTM SI Surface Area Analyzer, Scanning Electron Microscopy and X-ray diffraction. Results showed that abatement effciency of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs / Fs) in terms of total concentration averagely amount to 76% which was relatively higher than that of I-TEQ concentration averagely amount to 56%; the most concentration of toxic congeners as well as isomers of PCDDs / Fs decreased after mechanochemical treatment. The treated fly ash was characterized by a more homogeneous distribution of concaves as well as the significant decreasing in overall particle size and great enlargement in surface area.The major crystallization phases or intensities were considerably changed by mechanochemical treatment, of which a new phase containing chlorine formed may be a possible factor suggesting chlorination reaction occurring on the crystalline surface.