A new method for preparation of -amino acids was designed and realized by using a hydrogenation reaction as the key strategy. Ten benzyl -azidocinnamates were prepared from the ethyl 2-azidoacetate and aromatic aldehydes through the following combined processes of condensation of aldehyde and ester, saponification of methyl -azidocinnamates and esterification of the -azidocinnamic acids with benzyl alcohol. Then the hydrogenation of the benzyl -azidocinnamates was investigated, and the optimized conditions employed Pd/C (10% Pd) at 30% weight of the substrate as the catalyst, methanol as the solvent, and the pressure of hydrogen gas at 3 Mpa. The three-site conversion is featured with the combination of the reduction of azido group, the hydrogenation of C=C bond and the hydrogenolysis of benzyl ester, efficiently affording the corresponding -amino acids in 76~89% yields. Further, the substituents of chlorine and bromine on the aromatic ring of substrates were also removed during the hydrogenation reaction. The NMR analysis of the reaction mixture indicated that the conversion proceeded through the complicated hydrogenation process, while the ultimate product was clearly delivered. The pure -amino acids were obtained through a very simple filtration to remove the Pd/C catalyst.