Abstract: The present disclosure relates to a method for predicting an absorbance change by intermolecular interaction, and more particularly, to a method for predicting an absorbance change by the intermolecular interaction, in which absorbance is calculated according to the type of interaction force and bond between an amino acid and a target material using first-principles calculation based on density functional theory (DFT), thereby predicting a change in optical properties when the target material is adsorbed onto 20 amino acids or a peptide composed of two or more amino acids, and screening.