▎ 摘　　要

NOVELTY - A graphene fiber composite material preparation method involves preparing composite film of graphene and polymethyl methacrylate on copper foil. The composite film is transferred to the surface of the photonic crystal optical fiber by copper dissolution process, followed by removing polymethyl methacrylate in the composite film transferred to the surface of the photonic crystal fiber, and calcining to obtain the finished product. USE - Method for preparing graphene fiber composite material that is utilized as sensing material of the refractive index sensor for detecting concentration of the vulcanized hydrogen gas and sucrose. ADVANTAGE - The method enables preparing the graphene fiber composite material with high linearity response and excellent sensitivity, and high repeatability, in simple and cost effective manner.