Abstract: Solution, melt, and double-phase mixing technique were used to prepare PP/nano-SiO2 composites. The effect of mixing methodology and content of nano-SiO2 on the mechanical properties and microstructure of PP/nano-SiO2 composites was studied. It showed that the dispersion efficiency of nano-SiO2 was in the order of solution, double-phase, and melt mixing. When the content of nano-SiO2 exceed 3%，the composite based on double-phase mixing formed diphase structure. When the content of nano-SiO2 exceeded 5%，all three methods produced layered structure, which was not good for mechanical properties. Therefore, the content of nano-SiO2 of 3%，and double-phase mixing were preferred, which caused the tensile strength increased by 21. 3%，the elongation at break increased by 27.6%，and the impact strength increased by 131. 1%.

Key words: nano-SiO2, mixture technique, double-phase mixture technique, stratified structure, diphase structure