TiO2 nanocrystalline powders with high specific area were prepared using urea as the template by the sol-gel method. The samples were characterized by X-ray diffraction, N2 adsorption isotherms, and transmission electron microscopy. Urea plays a key role in the preparation process of TiO2 nanocrystalline powders. Large amounts of small urea aggregates were formed in the sol-gel process and decomposed during the calcination process, which results in the formation of large amounts of mesopores. Urea also inhibits the agglomeration and growth of the TiO2 nanoparticle, which facilitates the preparation of a TiO2 powder with smaller nanocrystal size. The above effects of urea may be the main reason of the as-prepared sample with very high specific surface area.