Pd/Al2O3 catalyst was successfully prepared by gamma-radiation induced reduction and showed much higher selectivity in the hydrogenation of methylacetylene and propadiene in propylene stream than catalysts prepared by chemical reduction and calcination method. Characterizations by TEM, XPS, and in situ FTIR proved that the irradiation process was beneficial in achieving uniform distribution of Pd particles on the surface of Al2O3 by strengthened Pd-support interaction. The irradiation process was also responsible for the dominant Pd(1 1 1) plane and the strong adsorption to target reactant of Pd sites, which we think are the reasons for the high selectivity of the catalyst. (C) 2012 Elsevier B.V. All rights reserved.