Ordered mesoporous SnO₂and mesoporous Pd/SnO₂have been successfully synthesized via nanocasting method using the hexagonal mesoporous SBA-15 as template. Two different procedures, impregnation technique and direct synthesis, were utilized for the doping of Pd in the mesoporous SnO₂. The results of small angle X-ray diffraction (SAXD), nitrogen adsorption-desorption and transmission electron microscopy (TEM) demonstrate that the SnO₂and Pd/SnO₂display ordered mesoporous structures and high surface areas. Wide angle X-ray diffraction (WAXD) and X-ray photoelectron spectroscopy (XPS) reveal tetragonal structure of SnO₂and the existence of Pd element. The sensing properties of mesoporous SnO₂and mesoporous Pd/SnO₂for H₂were detected. The sensor utilizing mesoporous Pd/SnO₂via direct synthesis method exhibits excellent response and recovery behavior and much higher sensitivity to H₂, compared to those using mesoporous SnO₂and mesoporous Pd/SnO2 via impregnation technique. It is believed that its high gas sensing performance is derived from the large surface area, high activity and well dispersion of Pd additive, as well as high porosity, which lead to highly effective surface interaction between the target gas molecules and the surface active sites.