Abstarct: The structure and intramolecular hydrogen bond (IHB) of Curcumin (CURC) have been investigated by means of density functional theory (DFT) at B3LYP/6-311++G**. The results obtained then were compared with those of 5-hydroxy-1,7-di(phenyl)hepta-1,4,6-trien-3-one (CURP), dibenzoylmethane (DBM),malonaldehyde(MA) and acetylacetone (AA). To investigate the effect of electron-donor and electron-acceptor substituents on the hydrogen bond strength, the charge distributions and the energy of electron delocalization in CURC studied using the (NBO) analysis. The estimated (IHB) and (EHB), the results of AIM analysis together with the values of 1HNMR for the enolated proton chemical shift and the vibrational frequencies of the OH bond for CURC, CURP, DBM and AA, indicate that the IHB in CURC is stronger than that in AA and weaker one than that in DBM. From AIM result, the interaction IHB of these compounds is partially covalent. The result the following trend in the hydrogen bond strength: DBM> CURC> CURP >AA >MA. The parameters related to NLO property showed that AA, MA are not good NLO materials but CURC, CURP are good ones. Frontier molecular orbital analysis and The small HOMO-LUMO energy gap for CURC, curp compound that indicated this molecule is chemical reactive.