Peptides optimally binding to solid surfaces are a promising candidate for adding bio-affinity, however, their binding states are not fully revealed. Herein, we realized a methodology for analyzing peptide adsorption states via employing nanowires and infrared (IR) p-polarized multiple-angle incidence resolution spectrometry (pMAIRS). Our methodology enabled to provide large crystalline surface for peptide adsorption, and enhance signal intensities. We found that a modelled peptide had different adsorption states among crystal axes. Analyzing peptide adsorption states can pave the way for controlling adsorbed states, and moreover, using full potentials of peptide.