Abstract: WO₃ nano-film was prepared by the Sol-Gel method using tungste and H₂O₂ as main materials,and sputtering a litter Pt on the WO₃ nano-film by DC reactive magnetron sputtering method in the paper.The constructure and the properties of the Pt/WO₃ nano-film were investigated.The results show that the Pt/WO₃ nano-films prepared by this method have good hydrogen-sensing properties;Its average thickness is 160nm;The film which annealed below 400℃ is amorphous and has good hydrogen-sensing properties;The film which annealed above 400℃ is crystalline and has less hydrogen-sensing properties;The amount of Pt is main factor influence the film’s hydrogen-sensing properties,the more the better.