Stoichiometric tungsten oxide (WO3) and tungsten bronzes have received much attention due to the energy-related functional performances. In addition, as a transition metal oxide, substoichiometric tungsten oxides have manifested their unique properties and exceptional potential to lots of applications; however, no other studies have concentrated on the oxygen-deficient tungsten oxides till now. Herein, this article presents the origin of structure and synthesis of W18O49 nanomaterials chiefly, and then the general introduction of different applications, including electrochemistry, photocatalysis, near-infrared shielding and phototherapy and sensing.