Hybrid nanocrystals of 8-hydroxyquinoline (8Hq) molecules and hydroxyapatite nanocrystals (HAp) were successfully prepared by a mechanochemical solid-state reaction. The hybrid nanocrystals exhibit a significant thermal stability and efficient photoluminescence peak at 500 rim, which were attributed to metal-ligand charge transfer at the interface between the oxygen atoms of 8Hq and the calcium ions of HAp, and the interfacial photofunctions were mechanochemically controlled. The interfacial bonding structures were also supported by a DV-X alpha molecular orbital calculation.