A composite photocatalyst (TiHAP@g-C₃N₄) consisting of Ti doped hydroxyapatite and g-C₃N₄ was synthesized through hydrothermal route. Its structure and optical property were characterized by various means and photocatalytic activity was evaluated through methyl orange (MO) degradation experiments. Results show that short rod-shaped TiHAP in the sample grows on the surface of g-C₃N₄. Both TiHAP and g-C₃N₄ maintain their original crystal shape and chemical structure. As-prepared TiHAP@g-C₃N₄ is of high purity with specific surface area of 107.92 m²/g, which is increased about 135% and 44% as compared with sole TiHAP and sole g-C₃N₄, respectively. The highest MO degradation rate of 96.35% is achieved within 120 min by TiHAP@g-C₃N₄ at the concentration of 1.0 g/L and pH 7. More than 80.02% of MO was removed in every of three cyclic tests, demonstrating good and stable photocatalytic performance of TiHAP@g-C₃N₄. Holes (h⁺) play the largest role in the MO degradation process, followed by ·O₂^- and ·OH. The constructed TiHAP@g-C₃N₄ heterojunction enhances light absorption, improves separation efficiency of photoelectrons-h⁺, and preserves more redox-prone TiHAP valence band h⁺ and g-C₃N₄ conduction band electrons. Therefore, as-synthesized TiHAP@g-C₃N₄ can be a promising catalyst in photocatalytic degradation.