▎ 摘　　要

Surface plasmon resonance (SPR) can generate a high intensity electrical field on the metal surface, which is widely used in the field of biosensor technology. The combination of SPR and mid-infrared spectroscopy has unique advantages in protein structure detection and analysis. Protein plays an important role in the identification and analysis of diseases. The change of protein conformation information is also the cause of some major diseases. In this paper, a grating SPR sensor based on graphene is proposed. SPR is excited by mid -infrared light, and a lot of energy is localized at both ends of graphene nanowires. Finite-Difference Time-Domain (FDTD) method is used to simulate the performance of the sensor. The parameters of the sensor are adjusted to satisfy the detection of protein secondary structure in amide I. The conformational information of protein in dry and water environments are calculated respectively. Graphene is used as sensing materials instead of metal. On the one hand, it is to avoid chemical reaction and prolong the life of the sensor. On the other hand, for protein biomolecules, graphene has stronger adsorption and field localization characteristics than metal. This sensor provides a new idea for protein detection.