A series of chlorinated hydroxyapatite(ClHAp) solid solutions composed of hydroxyapatite and chlorapatite were synthesized by the solid reaction method and were investigated using FTIR spectroscopy. In the experiment, vibration frequency of the hydroxyl group appeared at 3572 and 632 cm-1 in pure hydroxyapatite(HAp). When Cl- ions entered the crystal structure of HAp, a new absorption band was observed at 3494 and 673 cm-1respectively. These phenomena indicated that the hydrogen-bond forming in the channel structure made the stretching band shift towards a lower frequency and also resulted in the flexual band shift towards a higher frequency. A comparison with the FTIR spectra of fluoridated hydroxyapatite showed that the location and amount of vibration bands of the hydroxyl group in ClHAp were mainly affected by the hydrogen_bond and its surrounding structural variation.