Abstract: The effects of pH, initial fluoride ion concentration, reaction time and ionic strength on the adsorption of fluoride on natural sodium feldspar and potassium feldspar were studied through batch experiments. The results show that the pH_pzc of potassium feldspar and sodium feldspar are 8.0 and 6.5, respectively, which indicating the acidic conditions are more conducive to the adsorption of fluoride. The optimal pH for the fluoride adsorption reaction is 3. The increase of initial fluoride ion concentration can significantly promote the adsorption of fluoride on feldspar. At pH = 2, as the initial fluoride concentration increases from 20 mg·L⁻¹ to 310 mg·L⁻¹, the adsorption rate of fluoride on sodium feldspar was increased from 1.9% to 29.4%, and that on potassium feldspar increased from 2.8% to 40.2%. The adsorption process of fluoride on feldspar can be described by the pseudo second-order kinetic model and the Freundlich isotherm adsorption model. The ionic strength has no significant effect on the adsorption capacity of fluorine. These results indicated that the adsorption process is mainly controlled by chemical adsorption. Because potassium feldspar has a greater specific surface area and more adsorption sites, potassium feldspar has a greater adsorption capacity for fluoride than sodium feldspar under the same acidic conditions.