Dental implant made of pure titanium (Ti) has become one important option to restore the function of lost tooth. However, because of insufficient hardness, it is always scratched during oral hygieneprocedures. To improve its surface hardness,titanium nitride (TiN) coating was prepared. Soft tissue - implant interface is important for blocking bacteria invasion, therefore surface modification is necessary to improve biocompatibility of TiN for fibroblasts.In the present study, TiN coating was modified by hydrothermal treatment incalcium acetate (CaAc) solution and effect of hydrothermal treatment temperature was studied. After treatment,calcium (Ca) wassuccessfully combined into TiN surface and the surface morphology, roughness and hardness were not changed below 140 °C. It is expected that, surface modification with Ca by hydrothermal treatment could made TiN a promising dental implant coating.