A systematic research was performed about diffusion kinetics of adsorbing F- dissolved in water for carbonate hydroxyapatite (CHAP) from the natural hydroxyapatite which was modified by adulterating with CO32-. The result shows that the speed of F- adsorption is controlled by membrane diffusion when F- concentration is relatively low, which is expressed by the kinetic equation of diffusion Q=0.0005(Ci-C)(t-ti)+0.3967, or by vacancy diffusion when F- concentration is relatively high, which is expressed by the kinetic equation of diffusion ln[C(o, t)]=8.4718-0.5048lnt. Based on the feature of CHAP for adsorbing F- dissolved in water and its special channel of the structure of CO32- modified hydroxyapatite, models of vacancy diffusion and membrane diffusion were established.