The fiber pullout is a main failure after the fiber is broken in the tension of glass fiber reinforced polymer (GFRP) bolt. In this paper, the numerical analysis is done on the distribution of both fiber normal force and interface shear stress. The results show that, on the ideal interface, the fiber pullout occurs from the lower end to the upper end of the matrix gradually, and both the normal stress of the fiber and the shear stress of the ideal interface gradually increase from the lower end to the upper end. With the increase of the interface layer thickness, the shear stress concentration area on the interface is enlarged while the stress applied is reduced, and the displacement of GFRP deformation is increasing sharply. This means that the capacity of GFRP deformation is enhanced. As a soft elastic body, the interface layer with a smaller elastic modulus can make the fiber stress and the interface shear stress sharply small and well dispersed. In addition, the load can be effectively transferred to the reinforced phase fibers in a bigger interfacial layer elastic modulus with a certain strength.