Abstract: In this paper, we reported a simple hydrothermal method using micron level Al-Si alloy powder to prepare a novel core-shell structured catalytic support (Al-Si@Al₂O₃), with a shell of flaky Al₂O₃ layer and a core of Al-Si alloy. The analysis of FT-IR, XRD, SEM and TEM show that a nano-flaky AlOOH layer in situ grew on the surface of Al-Si alloy with an unreacted core via a hydrothermal process. And then after a 500^oC sintering process, the Pd/Al-Si@Al₂O₃ catalyst with highly dispersed Pd nanoparticles was prepared by immersion method. The effects of the size and Al content of Al-Si alloy on the prepared catalysts for styrene hydrogenation performance were researched. Meanwhile, water bath, alkali and acid treated Al-Si alloy as catalytic supports were compared, as well as traditional activated carbon and alumina. The results show that the Pd/Al-Si@Al₂O₃ catalyst has a better styrene hydrogenation performance when prepared using 5 μm and 88% content of aluminum via hydrothermal method. It has higher catalytic activity than that of activated carbon and alumina supports.