It can more effectively regulate the parameters of application of nano SiO₂ in the field of oil production by understanding the interaction process of Na+ on the surface of nano SiO₂ in saline water. In this paper，the amorphous nano SiO₂ particles was taken as an object of study，so that a nano SiO₂ particle model with both saturated stable silanol groups and deprotonated silanol groups was constructed. By using the molecular dynamics simulation experiments，this paper studied the interaction process between nano-SiO₂ particles and Na+ with different concentrations，including transportation，diffusion，recombination of hydrogen bonds， and the interaction energy. The results showed that in the system of nano-SiO₂ and NaCl solution，when Na+ migrated to a distance of 6.540 ? away from the surface of nano SiO₂ particles，the short-range force began to affect the movement of Na+ . When Na+ migrated to a distance of 2—3 ? away from the surface of nano SiO₂ particles，the charge exchange occurred between Na+ and the surface of nano SiO₂ particles，resulting in an oscillation motion of Na+ . At a NaCl concentration of 3 g/L，most Na+ underwent hydration with water molecules，which could form a stable solvation layer. The interaction between Na+ and nano SiO₂ particles was weak，so Na+ was more likely to diffuse in the solution. As the concentration of NaCl increased to 7 g/L，Na+ could break through the solvation layer. And then Na+ along with water molecules could be adsorbed on the surface of nano-SiO₂ particles. The migration ability of Na+ was weakened，the thickness of the double electric layer on the surface of nano-SiO₂ particles was narrowed，the interaction energy between nano-SiO₂ and Na + was enhanced，and then the stability of nano-SiO₂ was gradually destroyed. The diffusion coefficient of Na+ decreased from 1.39×10-4 ?2/ps to 3.75×10-5 ?2/ps. The thickness of the Stern layer on the surface of nano-SiO₂ decreased from 0.88 ? to 0.72 ?. The thickness of the Helmholtz layer on the surface of nano-SiO₂ decreased from 0.64 ? to 0.20 ?. The interaction energy between nano SiO₂ and Na + changed from -14 000 kcal/mol to -22 000 kcal/mol. The electrostatic interaction between Na + and nano SiO₂ particles was the main force to affect the surface properties of nano SiO₂ particles，while hydrogen bonding and van der Waals forces were secondary forces. The research conclusion could provide a basic theoretical understanding for the application of nano SiO₂ materials in the field of oil and gas drilling and other related industries.