An Si/TiO2 nanocomposite film, in which the Si nanoparticles as active materials were dispersed homogeneously into the mesoporous TiO2 matrix, was fabricated by a sol-gel coating method. The electrochemical properties of the Si/TiO2 anode for lithium ion batteries were investigated by cyclic voltammetry, galvanostatic charge-discharge tests, and electrochemical impedance spectrum. The mesoporous TiO2 successfully suppressed the aggregation and expansion of Si nanoparticles, and as tunnels, promoted the contact between Si nanoparticles and electrolyte. The Li diffusion coefficient in Si/TiO2 composite was estimated as 10(-12)-10(-13) cm(2) s(-1).