AIM:To investigate the reasons of exposure after intraorbital implantation of hydroxyapatite(HA) and the methods of preventing exposure.METHODS:Thirty-two patients suffered from exposure after intraorbital implantation of hydroxyapatite were retrospectively studied.RESULTS:The causes of exposure after hydroxyapatite orbital implantation included inappropriate operative procedure in 17 cases,mismatching hydroxyapatite in 6 cases,incorrect postoperative management in 5 cases and infection in 4 cases.After secondary surgery,the result of 32 patients were satisfactory.CONCLUSION:Careful operating and appropriate hydr-oxyapatite could avoid hydroxyapatite orbital exposure effectively.