Graded carbonate containing apatite coatings were formed on the surface of porous titanium alkali treated or alkali and heat treated by soaking in simulated body fluid. The results indicated that a porous network structure composed of sodium titanate and titanium oxide was formed on the surfaces after the porous titanium was treated by NaOH aqueous solution. Apatite nucleation on the surface of alkali and heat treated porous titanium at early stage was homogeneous. The contents of Ca, P and O decreased while that of Ti increased with the increasing of depth and a graded structure was formed near the surface of porous titanium. The porous titanium coating with the graded apatite is expected to be applied in clinical orthopedics to enhance bone implant bonding strength.