As a type of the novel semiconductor materials, tungsten oxide (WO3) is applied extensively in recent years for its electrochromic property. It has been widely used in many different applications, such as electrochromic windows, optical devices, fuel cells, gas sensors, and photocatalyst materials, etc. Based on the study on the preparation of platinum-doped WO3 films, we studied the optical and hydrogen sensitive properties of the films. In this work, firstly, the preparation method of the platinum-doped WO3 films was discussed. Secondly, we studied the transmissivity of the films. Thirdly, the restoration and the repeatability of the films was discussed. This work can provide theory support for the design of optic-fiber sensor for hydrogen concentration measurement.