The catalytic selectivity and activity of the catalyst PdCl2 can be improved significantly by using PPh3 as a ligand and NaBH4 as a reducing agent in the selective hydrogenation of cinnamaldehyde (CAL) to hydrocinnamaldehyde (HCAL) under atmospheric pressure. Adding a second transition metal component [NiCl2, Ni(OAc)(2), Fe(acac)(3), Co(OAc)(2)] to the catalyst can improve its selectivity further. PdCl2-0.5Co(OAc)(2)-PPh3 reduced by NaBH4 is the best catalyst.