TiO2 mesocrystal is a new anatase TiO2 single crystal with dominant {001} planes and increasing the area of high-energy surfaces,thereby exposing catalytically active sites for better performance.[1-2]TiO2 mesocrystal has the oriented superstructure of TiO2 nanocrystals which the nanomaterials have porous surfaces.[2-4] The porous surfaces greatly influence the performance of the nanomaterials in applications such as photoelectronics and photocatalysis.Compared with bulk single crystals,the improved photocatalytic activity of mesocrystals is supported by the increasing of the specific surface area.