Abstract: In order to explore the improvement effect of nano-SiO₂ and lime on silt in the Yellow River flood area,a series of tests including compaction test,unconfined compressive strength test,scanning electron microscope test and XRF test were conducted. This paper aims to study the effects of nano-SiO₂ and lime content on the compaction characteristics,compressive strength,water stability of silt. The microstructure and improved mechanism of the stabilized silt were analyzed. The results show that the maximum dry density and the optimum water content of the stabilized silt increase with the addition of nano-SiO₂ content. The addition of lime in the nano-SiO₂ stabilized silt reduces the maximum dry density,but increases the optimal water content. The combined improvement effect of nano-SiO₂ and lime is better than that of nano-SiO₂ alone. The unconfined compressive strength,cohesion and angle of internal friction increase most significantly. Compared with pure soil and nano-SiO₂ stabilized silt,the water stability of nano-SiO₂-lime stabilized silt is significantly improved. In the nano-SiO₂ stabilized silt,the nano-SiO₂ mainly serves to fill the pores between the soil particles. The combined application of nano-SiO₂ and lime can form cementing material in the silt,play a role of bonding and filling,and greatly improve the strength of the silt.