Abstract: Porous SnO₂ nanostructured film gas sensor was fabricated by spray pyrolysis route using tin chloride pentahydrate (SnCl₄•5H₂O) and PdCl₂ dopant as starting material. The phase, morphology and porous microstructure of the samples were characterized by XRD, FE-SEM and BET, respectively. Hydrogen sensitivity test reveals that the nanostructured gas sensor processes rapid response in 10^-4concentration of H₂ at temperature below 150 ℃, and the phenomenon can be attributed to pore structure and the improvement of gas absorption and catalytic effect of Pd dopant.