In this study, octadecylamine (ODA)was employed to graft-modify graphene oxide (GO), followed by reduction with hydrazine hydrate (N2H4). This process effectively improved the dispersion stability of graphene in organic solvents, and successful modification was confirmed through various characterization techniques including Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). A bio-based flexible strain sensing material was fabricated through solution blending and compression molding processes, utilizing bio-based Eucommia ulmoides gum as the matrix. An efficient conductive network structures were established via the synergistic effect of modified graphene and carbon nanotubes (CNT). The dispersion of fillers within the matrix and the sensing performance of the flexible material were systematically investigated using a universal testing machine, Fluke data acquisition instrument, and transmission electron microscopy (TEM). The results demonstrated that the modified graphene and carbon nanotubes achieve uniform dispersion in the gutta-peritoneum matrix, which makes the sample obtain excellent electrical conductivity, and the resistance of the sample is reduced by 2 orders of magnitude compared with the sample filled with the unmodified filler. The Eucommia ulmoides gum flexible sensing material exhibited outstanding sensing performance in low-strain ranges, characterized by a gauge factor of 35, rapid response time of 56 ms, and remarkable stability.