Abstract: A series of nano SiO₂ grafted with organosilane (HB-2200), nano SiO₂ grafted with amino (HB-2205N), nano SiO₂ grafted with double bond (HB-2205D) and nano SiO₂ grafted with amino-double bond (HB-2205ND) groups were prepared through liquid phase in-situ surface modification method. The structure and properties of nano SiO₂/solution polymerized styrene butadiene rubber-polybutadiene rubber (SSBR-BR) composites were characterized by TEM, SEM and rheometer. The results show that compared with the unmodified nano SiO₂, the compatibility between surface functionalized nano SiO₂ and rubber matrix is improved, Payne effect is reduced, the interaction between nano SiO₂ is weakened, and the dispersion of nano SiO₂ in SSBR-BR is improved. Compared with nano SiO₂/SSBR-BR composite, the mixing torque of HB-2200/SSBR-BR composite is reduced by 35.7%, the mixing energy consumption is saved by 15%, the interfacial bond between the filler and the rubber is strengthened due to the increase in the content of bound rubber, and its tensile strength is increased by 60%. The dynamic mechanical and abrasion performance analyses show that the reactive double bond group grafted on the surface of SiO₂ could improve the wet slip resistance of HB-2205D/SSBR-BR composite by 40% and reduce the rolling resistance by 43%. Nano SiO₂ surface grafted with reactive double bond could reduce its rolling resistance and improve its resistance to wet slip, without sacrificing the wear resistance of HB-2205D/SSBR-BR composite. It provides the basic raw materials for the preparation of high-performance tires.