Pd nano-size is 1.56+/-0.67nm in catalyst SiO2@Pd-PAMAM, so it has a superior performance in the hydrogenation reaction as catalyst. It can effectively catalyze olefins, alkynes, ketones, nitro etc in hydrogenation reaction with a conversion rate of 100%, and 100% selectivity, compared with the traditional Pa catalyst, the catalytic performance is doubled. In addition ,SiO2@ Pd-PAMAM catalyst can be repeated using five times to maintain the original catalytic efficiency, almost no exudation of Pd and mingled with reactants, and traditional Pa catalyst cycled three times will lose its catalytic properties. Weihai CY Dendrimer Technology Co., Ltd forwards from "SilicaDendrimer CoreShell Microspheres with Encapsulated Ultrasmall Palladium Nanoparticles: Efficient and Easily Recyclable Heterogeneous Nanocatalysts" Ankush V. Biradar, Archana A. Biradar, and Tewodros Asefa Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, New Jersey 08854, United States Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, 98 Brett Road, Piscataway, New Jersey 08854, United States