Abstract: In order to prepare the composites of grafted polyethylene and SiO₂, and endow it with new special properties, low-density polyethylene graft polystyrene (LDPE-g-PS) was prepared by pre-irradiation and suspension graft technique firstly, and PS modified nano-SiO₂ (PS@nano-SiO₂) were prepared by surface grafting. Then, PS@nano-SiO₂/LDPE-g-PS composites were prepared by melt blend of LDPE-g-PS and PS@nano-SiO₂. Finally, the structures and properties of the materials were investigated by FTIR, SEM, DSC and electronic tensile machine etc. The results indicate that the PS has been grafted onto LDPE and nano-SiO₂ respectively. In PS@nano-SiO₂/LDPE-g-PS composites, SiO₂ reaches nano-scale dispersion in LDPE-g-PS, and forms unique fibrous network structure. The impact strength of 2wt% PS@nano-SiO₂/LDPE-g-PS composite improves by 99.3% comparing with that of LDPE-g-PS. Comparing with LDPE-g-PS, crystallization temperature of PS@nano-SiO₂/LDPE-g-PS composite increases, and the breakdown field strength is 1.4 times higher than that of LDPE. The conclusions obtained show that the properties of PS@nano-SiO₂/LDPE-g-PS composites are better.