In this paper, the PdO_x nanoparticles modified SnO₂ are prepared using sputtering and wet chemical methods. The SnO₂ nanoparticles are separately added to a concentration of 0.75% to 10% PdCl₂ to obtain a PdCl₂/SnO₂ composite material, which is calcined for 1 to 2 h at the temperatures of 120 °C, 250 °C, 450 °C and 600 °C. The PdO_x/SnO₂ nanocomposite was characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffractometry (XRD) and transmission electron microscopy (TEM). Microstructural observations revealed PdO_x with different chemical states attached to the surface of SnO₂. Hydrogen response change tests were performed on the obtained PdO_x/SnO₂ gas sensing materials. The results show that the high gas sensing performance may be attributed to the contribution of the PdO_x-loaded SnO₂. In hydrogen, the best sensitivity response was attained at 80 °C, which is 60 times that of pristine SnO₂. It clarifies the role of PdO_x in the gas sensing mechanisms.