A Conotoxin is one of a group of neurotoxic peptides isolated from the venom of the marine cone snail, genus Conus. Conotoxins, which are peptides consisting of 10 to 30 amino acid residues, typically have one or more disulfide bonds. Conotoxins have a variety of mechanisms of actions, most of which have not been determined. However, it appears that many of these peptides modulate the activity of ion channels. Over the last few decades Conotoxins have been the subject of pharmacological interest. Parameters such as FT­–IR and Raman vibrational wavelengths and intensities for single crystal Alpha–Conotoxin, Omega–Conotoxin and Mu–Conotoxin are calculated using density functional theory and were compared with empirical results. The investigation about vibrational spectrum of cycle dimers in crystal with carboxyl groups from each molecule of acid was shown that it leads to create Hydrogen bounds for adjacent molecules. The current study aimed to investigate the possibility of simulating the empirical values. Analysis of vibrational spectrum of Alpha–Conotoxin, Omega–Conotoxin and Mu–Conotoxin is performed based on theoretical simulation and FT–IR empirical spectrum and Raman empirical spectrum using density functional theory in levels of F/6–31G*, HF/6–31++G**, MP2/6–31G, MP2/6–31++G**, BLYP/6–31G, BLYP/6–31++G**, B3LYP/6–31G and B3LYP6–31–HEG**. Vibration modes of methylene, carboxyl acid and phenyl cycle are separately investigated. The obtained values confirm high accuracy and validity of results obtained from calculations.