ABSTRACT: Tin (Sn) films with a thickness of 400 nm were prepared by the thermal evaporation method, and the samples were then oxidized at 300 and 400 °C. X-ray diffraction was used to study the crystal structure and phase of the film before and after oxidation. The surface morphology was examined by AFM, and the optical properties were analyzed by spectroscopy in the wavelength range of 200-1100 nm. It was observed that the maximum transmittance was less than 70%, and the energy gap increased with increasing oxidation temperature. The film oxidized at 400 °C was tested for H2S gas sensing when the film was exposed to different temperatures and a fixed concentration (20). It was found that the sensitivity increased with increasing temperature, with the highest sensitivity being 0.806, the response time being 22.5 seconds, and the recovery time being 49.5 seconds at 200 °C.