Chemisorption of Cinnamaldehyde on Ni (100) surface has been studied by means of model nickel cluster Ni28 with density functional theory (DFT).Cinnamaldehyde adsorbed perpendicularly to the surface and bonded to the metal atom via an oxygen-metal interaction took a strong chemisorption.Such chemisorption led to electron transfer from Cinnamaldehyde molecule to nickel cluster.In the metal complexes Ni-Cinnamaldehyde,the σ-binding via the lone-pair electrons of O atom and Ni atom was observed.The binding energy is up to 107 kJ·mo1-1.The backbone of Cinnamaldehyde molecule changes a lot due to adsorption,which can be indicated by the variety of bond lengths,bond orders,bond angles,IR spectroscopy and hybridization of chemical bonds.NBO analysis explained these changes and why Cinnamaldehyde molecule was activated by the chemisorption.