Abstract: Taking CaO,NaOH,Na2CO3,et al modify the fly ash with dry and wet process,some samples were dealt with thermal shock.The phrase transformation was analyzed according to XRD spectrum.The results show that the samples which mixed with CaO,then incinerate,immersed with H2SO4 and the samples which mixed with Na2CO3,then incinerate,have more diffraction peaks,the former has more compact diffraction peaks after thermal shock.So the fly ash samples has better adsorption property which mixed with CaO,then high temperature incinerate,immersed with H2SO4（the volume ratio of H2SO4 to H2O is 1∶4.）.