Abstract: Nano-SiO₂ layer was obtained on the jute fibers by sol-gel method, and nano-SiO₂ deposited jute fiber/polypropylene composites (n-SiO₂@jute fiber/PP composites) were prepared by molding process. The molecular model of the multi-phase interfaces for n-SiO₂@jute fiber/PP composites was established by molecular dynamic (MD) simulation. Combined with the analyses of the impact performance and fracture morphologies for n-SiO₂@jute fiber/PP composites, the multi-phase interface structure and toughening mechanism of the compo-sites were revealed. The impact toughness of n-SiO₂@jute fiber/PP composites is increased by 54.87% than that of the control ones. n-SiO₂ layer forms an interphase between jute fiber and PP by C—O—Si chemical bond and the mechanical interlocking of molecular chains, which enhances the interface binding energy of jute fiber/PP compo-sites by 27.22%. When the impact fracture of the composites occurs, n-SiO₂ interphase causes the crack deflection at the interface, which will absorb more fracture energy by increasing the crack propagation path and decreasing the crack propagation velocity. Additionally, the multi-phase interfaces with good bonding performance make the PP surrounding n-SiO₂ interphase undergo plastic deformation during the impact failure process, absorbing massive impact energy. Moreover, the multi-phase interfaces transfer the part of impact energy from PP to jute fibers effec-tively, causing the internal debonding of the jute fibers and thus consuming more impact energy. This is because the interface bonding strength between the fibrils in the jute fibers is stronger than that between the jute fibers and PP.