Titanate nanofibres can be produced by reacting concentrated NaOH solution with a titanium compound or titania (even a rutile mineral) under hydrothermal conditions (200°C or below). They have a large surface to volume ratio, and are able to react with dilute acids or transform to TiO₂ polymorphs at moderate temperatures. These properties are utilized to fabricate a series of efficient photocatalysts. They include nanofibres of mixed anatase and TiO₂(B) phases, TiO₂(B) nanofibres covered with anatase nanocrystals, metal ions doped nanofibres of the mixed titania phases, single-phase anatase nanofibres, TiO₂ nanofibres coated with other oxides. Such studies not only result in catalysts that possess high photocatalytic activity and can be readily dispersed into and separated from liquid phase, or exhibit considerable activity under visible light; but also provide us unique opportunity to acquire fundamental information. For instance, the detail structure of interfaces between two titania polymorphs because the nanofibre morphology is particularly suitable to the transmission electron microscopy study. The function of the interfaces in the photocatalysis processes is clarified. We also have better understanding of the pathways of the phase transitions from titanate to a titania polymorph or from one polymorph to another, and reactivity of the nanofibres to various chemicals. This knowledge can be use to design different nanostructures, particularly efficient photocatalysts.