In this work, the rutile mesocrystals TiO₂ were synthesized by hydrothermal method using layered titanate HTO (H_4x/3Ti_2-x/3□ _x/3O₄?nH₂O) as the precursor. By means of X?ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and other testing methods, the effect of reaction temperature on the synthesis of rutile?type mesoscopic TiO₂ crystal material by means of topological structure transformation was studied. The results reveal that rutile TiO₂ can be obtained under the condition of pH 0.5 of the reaction system, and with the gradual increase of the reaction temperature, the rutile?type mesoscopic TiO₂ crystal material is formed at 120 ℃. Taking Rhodamine B (RhB) as the pollutant model for degradation experiments, the photocatalytic activity of rutile mesocrystals TiO₂ is significantly higher than that of other samples. Experiments on dye?sensitized solar cells (DSSCs) show that the mesocrystals structure formed at 120 ℃ is conducive to the rapid migration of photogenerated carriers, thus obtaining high cell characteristics.