Abstract: TiO₂ nanobelts were prepared by hydrothermal synthesis and acid treatment, then calcination at different temperatures. And subsequently Pt nanoparticles were deposited on the TiO₂ nanobelts. Pt/TiO₂ catalytic properties were investigated in the oxidation of formaldehyde. These catalysts were characterized by various techniques and the characterization results showed that the applied thermal treatment temperature greatly influenced the phase composition and surface structure of TiO₂ nanobelts, as well as the number of oxygen vacancies and hydroxyl groups on the surface. The Pt/TiO₂ nanobelts thermally treated at 600 °C had more oxygen vacancies, which were conducive to the activation of adsorbed oxygen, formed more Ti-(OH)_x-Pt species, and showed higher catalytic activity. At 25 °C and relative humidity of 55%, the conversion of formaldehyde reached 91.6%.