Abstract: The Ca-Fe-Mg composites for fluorine ion removal are prepared using co-precipitation method.The best experiment conditions to prepare the adsorbent are defined, with the Ca/Fe/Mg mole ratio of 1:2:2, pH=9 and the calcination temperature of 100℃.The fluorine absorption experiments of adsorbent are performed.It shows the absorbent still has the good adsorption properties.The adsorption properties are influenced by and less by and adsorption is characterized by applying in alkaline conditions and less influence by co-existing anions, and is an absorbent for fluorine removal with best absorption properties, widespread use and low cost, which can be used to remove the water fluorine in mining areas.