Abstract: The monodisperse and precipitated silica (SiO₂) were modified by coupling agent Si747 in liquid phase and the SiO₂/natural rubber (NR) composites were prepared by latex compounding technology. The structure and properties of Si747-modified SiO₂/NR composites were characterized by rubber process analyzer, DMA and SEM. The results show that in terms of the vulcanization characteristics, compared with the unmodified SiO₂, the scorch time and the positive vulcanization time of the composites obtained by using coupling agent Si747 modified SiO₂ and NR are shortened, which promoted the vulcanization process of rubber. The scorch time and the positive vulcanization time of the monodisperse SiO₂/NR vulcanizates were longer than that of the precipitated SiO₂/NR vulcanizates before and after SiO₂ modification; Considering the physical and mechanical properties, compared with unmodified SiO₂/NR vulcanizate, the tensile strength of the modified monodisperse SiO₂/NR vulcanizate is increased by 17.4%. The resilience and wear resistance are improved by 9.5% and 32.6%, respectively. The heat-build up is reduced by 24.3%. In terms of dynamic viscoelasticity, the modified monodisperse SiO₂/NR vulcanizate has the lower Payne effect, the better dispersibility of the filler and the weaker filler network compared with the modified precipitated SiO₂/NR vulcanizate. In terms of dynamic mechanical properties, the performance in wet-slip resistance of modified monodisperse SiO₂/NR vulcanizate is slightly lower than that of the modified precipitated SiO₂/NR vulcanizate, but the rolling resistance is much better than the latter and saves more energy.