Use simple magnesium salt as raw material, the magnesium oxide precursor powder was synthesized, and then the spheroidal magnesium oxide (SMO) was synthesized by controlled temperature calcination. Then lanthanum-modi ed spheroidal magnesium oxide (LSMO) was prepared by impregnation. The SMO and LSMO were characterized by X-ray diffraction (XRD), eld emission scanning electron microscopy (SEM), N 2 adsorption-desorption, infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). For the initial uorine concentration of 10mg/L uoride solution, the maximum uoride removal e ciency of 15% impregnation ratio lanthanum modi ed spheroidal magnesium oxide (15LSMO) is 93.1%, which is higher than 82.7% of SMO, far lower than the international standard 1.5mg/L. In addition, in the pH range of 2-11, and in the presence of interfering ions, the effect of 15LSMO also meets the international standards for uoride removal. For the enhancement of uoride removal effect of de uoridation agent, lanthanum modi ed material de uoridation mechanism changes have profound insights.