Epoxy group-functionalized biobased elastomer poly(dibutyl itaconate-ter-isoprene-ter-glycidyl methacrylate) (PDBIIG) was synthesized via redox emulsion polymerization using glycidyl methacrylate (GMA) as the epoxy group-included monomer. The silica/PDBIIG nanocomposite was prepared without adding silane coupling agents. The ring-opening reaction, which occurred between the hydroxyl groups on the silica surfaces and the epoxy groups of the PDBIIG chains during mixing and vulcanization, was confirmed via bound rubber tests and Fourier transform infrared spectroscopy. This reaction was facilitated through heat treatment at 150 degrees C effectively. The introduction of covalent bonds significantly improved the interfacial interaction and dispersion of silica, which was indicated by transmission electron microscopy and rubber process analyzer (RPA) results. With the same silica loading and compounding procedure, the inclusion of 3.7 wt % GMA. increased the modulus at 100% strain by 150.0% and the modulus at 300% strain by 152.3%. For the dynamic mechanical properties, the nanocomposite with GMA exhibited higher wet skid resistance and lower rolling resistance than the nanocomposite without GMA.