Prions are the infectious agents of the transmissible spongiform encephalopathies. The sequence 113-120 of Prion proteins is thought to be the most highly amyloidogenic peptide. The chromatographic retention behaviors of Prion 113-120 peptide on C18-column were studied under reversed-phase high-performance liquid chromatographic conditions with isocratic elution. When aquo-acetonitrile mobile phases were used, the temperature-depending relationships of lnkw and Van′t Hoff plots of both peptides with free termini and with capped termini were simple. The results demonstrated that the conformations adopted by both peptides in aquo-acetonitrile mobile phases were relatively stable, and could not be perturbed by temperature. When aquo-methanol mobile phases were used, the temperature-depending relationships of lnkw and Van′t Hoff plots of peptide with free termini were more complicated than that of peptide with capped termini. These results demonstrated that the conformations adopted by peptide with free termini in aquo-methanol mobile phases were relatively unstable and could be perturbed by circumstance. All these results further demonstrate that the sequence 113-120 could play an important role in the conformational change of Prion proteins.