Porous network of weakly crystallized sodium titanate gel layer was formed on the surface of titanium alloys (Ti6Al4V) after treated by NaOH alkali solution. The pore size increases with the alkali concentration and treating time. The sodium titanate gel layer can induce the deposition of octacalcium phosphate and /or apatite orientated along (002) plane from the fast calcification solution, and bone like apatite layer from the simulated body fluid without orientation. The two factors responsible for the composition and depositing speed of the softly compounded calcium phosphate layer on alkali treated titanium alloy are the alkali treatment conditions and the ion species, their concentrations and the pH value of the calcium phosphate solution.