Polyaryl ether aminediacetic acid dendrons (Gn-NA) were synthesized and used as stabilizer for preparing Pt nanoparticles. The resulting Pt nanoparticles have mean particle size from 2 to 5 nm depending on dendrimer generations and the molar ratio of metal/dendrimer. Most of the surface of the as-prepared platinum clusters, on which the dendrimers attached on the platinum core via the interactions between carboxyl groups and surface Pt atoms, remains unpassivated. Turnover frequencies for the hydrogenation of phenyl aldehydes to phenyl alcohols change from 91 to 25 depending on the dendrimer generation and substrates under an atmospheric pressure of H-2. The Pt particles capped with Gn-NA are stable during the catalytic hydrogenation process and can be easily recovered and reused. The result suggests the effectiveness of polyaryl ether aminediacetic acid dendrimer as a stabilizer for the preparation of Pt nanoparticle catalysts.