Abstract: In order to improve the adsorption efficiency of adsorbent for removal of fluoride in wastewater, the fly ash cenospheres modified with calcium were prepared by annealing method. Through the Box-Behnken response surface methodology design of adsorption fluorine experiments, the effects of adsorption factors and their interactions were investigated, and the optimal adsorption conditions were determined. Scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and specific surface area analysis (BET) were employed to characterize the physicochemical properties of the adsorbents. The mechanisms of fluoride adsorption were investigated by means of adsorption kinetics and isothermal adsorption experiments. The results suggested that:(1) The initial F^- concentration and adsorption temperature significantly affected the removal efficiency of F^-; the optimal adsorption conditions were at pH of 5.0, initial F^- concentration of 125 mg/L and adsorption temperature of 40℃. (2) The experimental kinetic data were well fitted by the pseudo-second-order model, which indicated that the dominant adsorption belonged to the chemisorption. The Temkin isotherm model was more suitable for describing the adsorption equilibrium than the Freundlich or Langmuir isotherm model. (3) The SEM, EDS and BET analyses indicated that Ca-containing cluster materials with irregular surface and porous structure were formed inside the fly ash cenospheres, which led to increases in porosity and specific surface area. The XRD analysis showed that the removal of F^- from water by the fly ash cenospheres was mainly via the ion-exchange. These results showed that the maximum F^- adsorption rate of the fly ash cenospheres modified with calcium and prepared from industrial waste is 93.59%, and the low-cost adsorption material has potential application.