Pd/γ-Al2O3-IM, Pd/γ-Al2O3-DP and Pd/γ-Al2O3-SA catalysts with 0.03 wt% Pd loading for catalytic oxidation of toluene were respectively prepared by the impregnation, deposition-precipition, and self-assembly methods using PdCl2 and Pd2(dba)3 as precursors. The temperature for conversion of 98% toluene (T98) over Pd/γ-Al2O3-SA catalyst was 220 ℃ under the conditions of toluene volume fraction at 0.1% and space velocity (SV) at 18000 mL/（g•h）, which was 40 and 75 ℃ lower than those of Pd/γ-Al2O3-DP and Pd/γ-Al2O3-IM. The catalysts were characterized by N2 adsorption-desorption, XRD, TEM, XPS, H2-TPR. The results indicated that Pd/γ-Al2O3-SA catalyst possessed the largest specific surface area (345 m2/g) and pore volume (0.52 cm3/g), the smallest average diameter (5.0 nm) of Pd nanopaticles (NPs), and the main active PdO species were well-dispersed on the surface of the γ-Al2O3 support. Besides, the strong metal-support interaction (SMSI) between PdO and γ-Al2O3 promoted its performance in catalytic oxidation of toluene.