Abstract: Towards miniaturization, integration and high selectivity and sensitivity of solid electrolyte gas sensors have become the future development trend. In this paper, WO₃ gas sensor-sensitive electrode materials were successfully prepared by magnetron sputtering. The structure, composition, and morphology of WO₃ were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The XRD results show that when the annealing temperature is greater than 400°C, WO₃ has a (200) diffraction peak, and with the increase of annealing temperature, the diffraction peak increases significantly, indicating that the crystallization quality of WO₃ is improved. The SEM test results show that with the increase of annealing temperature, the grain size of the film gradually increases, and when the annealing temperature reaches 500 °C, the grain size reaches 23 nm, which is consistent with the calculation result of Scherrer's formula. The EDS results show that the annealing temperature also has a great influence on the composition of the film. The O: W atomic ratio increases from 2.7 to 3.2, which is consistent with the XPS results. The gas sensing performance test at high shows that the prepared WO₃ sensitive electrode has obvious gas response behavior to NO₂. This study provides a research basis for the preparation of miniaturized, highly selective and sensitive solid electrolyte gas sensors.