The precursor solutions containing TiO2 sol for nanoporous films were prepared by hydrolyzing titanium(IV) isopropoxide and adding trehalose dihydrate. The porous and thick TiO2 film was prepared by dip-coating technique on glass substrate and heating at 500 °C. The film was composed of nano sized particles (10-20 nm) and pores (7 nm). The specific surface area of the film was 163 m2/g. The film had humidity-sensitive electrical resistance at room temperature.