A biomimetic method has been used to prepare silicon-substituted hydroxyapatite coatings on titanium substrates. The surface structures of the coatings were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Fourier transformed infrared spectroscopy (FTIR). Si substituted hydroxyapatite (Si-HA) coatings with different Si contents were deposited successfully on the titanium substrate by immersing the pretreated titanium substrate into silicon containing supersaturated solutions (SSS) with different SiO 3 2concentrations. The pretreatment of the Ti substrate in a mixed alkaline (NaOH + Ca(OH 2 )) followed by a heat treatment produced a 3D porous surface structure with rutile and CaTiO 3 as main phases, which contributed mainly to the fast precipitation and deposition of Si-HA. FTIR results showed that Si in the Si-HA coating existed in the form of SiO 4 4-groups. The cross-section microstructure was observed by scanning electronic microscopy and the shear strength was tested. The coating was about 5-10 ฮผm in thickness and no interval was observed at the interface between the coating and the substrate. Shear strength testing showed that Si-HA/Ti exhibited higher shear strength than HA/Ti due to the existence of the SiO 4 4-group in the coating.