The performance of TiO2 materials in environment and energy applications strongly depends on the crystalline properties, such as crystal phase, crystallinity and crystal orientation. However, it's a great challenge to control and improve all the crystalline properties. Meanwhile, efforts have been made to improve crystalline properties of the pore walls in mesoporous TiO2. Unfortunately, the poor crystalline properties of pore walls are inherent issues since frameworks collapse in crystallization. Mesoporous frameworks with definite crystalline properties, therefore, would be fantastic structures for TiO2. Obviously, the difficulty is doubled. Based on the unique crystal structures and versatile phase evolution of K2Ti2O5, we obtained high surface area mesoporous TiO2 nanofiber with definite and controllable crystalline properties, including anatase-TiO2(B) bicrystalline, high crystallinity and one-dimensional crystal orientation. The synthesized TiO2 shows promising applications in photocatalytic H2 evolution, water purification, photovoltaic solar-cell, Li-ion battery, and compacted catalyst support.