Abstract: In order to improve compatibility between hydroxyapatite particles and polylactide in composite bone repair materials, vinyl-terminated polylactide was synthesized.This vinyl-terminated polylactidc was reacted with double bond containing silane, a novel compatilizer was obtained. Through the condenration between the hydroxyl groups hydrolyzed from the silane and those on the hydroxyapatite, the compatibility of polylactidc and hydroxyapatitc was improved.Fouricr Transform Infrared Spectra confirmed the compatilizer possessing designed structure. Scanning Electron Microscope photographs showed that in the composite containing the compatilizer, the border between polylactide and hydroxya-patite became smeared，which was the evidence of improved compatibility.

Key words: compatibilizcr, composite bone tissue repair material, hydroxyapatitc, polylactidc