In order to improve the dispersibility of hydroxyapatite,hydrothermal method with citric acid as chelating agent was used to prepare hydroxyapatite with improved dispersibility and citric acid was added to improve the dispersion of the sample,reduce the grain size,and adsorb fluorine ions in simulated water samples. The main parameters of hydrothermal synthesis of hydroxyapatite were optimized by single factor test and response surface method. Hydroxyapatites with different ratio of citric acid were characterized by five techniques such as：X-ray Diffraction (XRD),Fourier Transform Infrared Spectroscopy (FT-IR),Scanning Electron Microscope (SEM),Nitrogen Adsorption/Desorption Experiment and Energy Dispersive Spectrometer (EDS). The results show that the addition of citric acid will significantly affect the micro morphology of hydroxyapatite in nano scale. Box-Behnken design with three-levels and three-factors has been applied to determine the optimal parameters such as hydrothermal time (4-8 h),temperature (140-160 ℃),citric acid dosage (0.5%-1.5%) on removal of fluoride from simulated solution. The results show that the optimal conditions are 147 ℃ of hydrothermal temperature,eight hours of hydrothermal time,and 0.5% of citric acid addition. Under the best process conditions,nano hydroxyapatite with high dispersion is successfully obtained. For simulated water samples (fluorine ion concentration is 6 mg/L),the fluoride removal efficiency reaches 44.6%,The fluoride removal capacity is 2.678 mg/g,which is higher than the test value of commercially available hydroxyapatite under the same test conditions (1.437 mg/g). According to thermodynamic [JP+2]parameters，adsorption of fluoride is a spontaneous process(ΔG0＜0) with reduced endothermic (ΔH0<0) and increased entropy (ΔS0＞0)．The kinetic simulation of fluoride absorption by hydroxyapatite is conformed to pseudo second-order kinetics. The prepared hydroxyapatite samples were made into particles and evaluated by continuous adsorption device. The fluoride concentration in the effluent remained below 1.0 mg/L for 9 days,which means the hydroxyapatite made in lab has a significant removal effect of fluoride.