This work demonstrated that mesoporous TiO= (meso-TiO2) with con- trollable mesoporous and crystalline structures can be facilely prepared by using poly (ethylene glycol) (PEG) as structure-directing (SD) agent and peroxotitanic acid (PTA) as precursor. Meso-TiO2 with high specific surface area (157 m2.g-1), pore volume (0.45 cm3.g-1) and large mesopore size of 13.9 nm can be obtained after calcination at 450℃. Such meso-TiO2 also shows relatively high thermal stability. BET surface area still reaches 114 m2-g-1 after calcination at 550℃. In the synthesis and calcination process, PEG that plays multiple and important roles in delivering thermally stable and tunable mesoporous and crystalline structures shows to be a suitable low-cost SD agent for the controllable preparation of nanocrystalline meso-TiO2. The photocataiytic activity tests show that both high surface area and bi-crystallinity of obtained meso-TiO2 are important in enhancing the performance in photo-decomposing Rhodamine B in water.