Ionic liquid 1-allgl-3-methylimidazolium chloride(AMI) was employed to modify silica, and modified SiO₂/NR composites was prepared.Silica microstructure before and after modification was characterized by Fourier transform infrared spectroscopy(FT-IR), X-ray photoelectron spectroscopy(XPS) and scanning electron microscope(SEM). The effect of AMI on structure and performance of SiO₂/NR composite was studied. The result shows thatthe dispersion of AIM-modified SiO₂ improves obviously,the practical distribution size decreases in rubber matrix, interface interaction is strengthened between silica andrubber matrix, the content of bound rubber increases evidently, overall mechanical property of composite material is improved. When the AMI content is 2 phr, the dispersion of silica is the best in rubber matrix, the distribution size is the minimum, the content of bound rubber reaches the maximum value, overall mechanical property of composite material is the best. Compared with non-modified SiO₂/NR composites,the tensile strength of AMI-SiO₂/NR composite increases by 18%, tear strength advances by 41.4%, modulus at 300% elongation improves by 39.2%, modulus at 100% elongationenhances by 25%.