摘要： Graphene ?ber has attracted much attention due to its potential applications in supercapacitors, dye-sensitized solar cells, actuators, motors, stretchable circuits and functional composites, owing to its high electrical conductivity, tensile strength and good ?exibility. The high tensile strength of graphene ?ber renders it promising candidate as the reinforcement in the composites. The interface is the key element for the ?ber-reinforced composites; however, there is no study about the interfacial evaluation about the graphene ?ber reinforcement composites. Herein, in this study, we fabricate the high-strength graphene ?bers (up to 890.1 MPa) through the wet spinning and thermal annealing method, make the graphene ?ber-reinforced single-?ber composite, and develop a novel and facile fragmentation test to quantitatively evaluate the interfacial performance of graphene ?ber. Graphene ?ber has the interfacial shear stress (IFSS) of 60.6 MPa, exhibiting one of the highest IFSS among the carbon nanotube yarns and commercial carbon ?bers composites. The superior interfacial performance of graphene ?ber is attributed to the surface wrinkles and grooves, which establishes strong physical interlocking between graphene ?ber and resin, favoring for the stress transfer. This work will pave the way for the development of graphene ?ber-reinforced composites.