The insufficient storage performance of emulsified asphalt has always been a problem affecting its application，and there have been studies in China on nano-SiO2 particles as additives to improve the stability of emulsified asphalt，but the effect is not obvious.Based on the principle of Pickering emulsion，nano-SiO2 with surface modification was used as an emulsifier to directly emulsify matrix asphalt，and whether its stability improvement effect on emulsified asphalt is better than nano-SiO2 as a modified additive was explored.Firstly，three emulsified asphalt were prepared，namely ordinary modified emulsified asphalt A，emulsified asphalt B with nano-SiO2 as a modified additive，and emulsified asphalt C based on the new nano-SiO2 Pickering emulsion emulsification.Then，through optical microscopy and SEM，the microscopic morphological differences of the surface structure of the emulsified asphalt with nano-SiO2 particles as emulsifiers and modified additives were explored，and the different morphologies of emulsion particles in three emulsified asphalt were analyzed.Finally，the indoor emulsified asphalt test and particle size analysis of emulsion particles demonstrated the difference between nano-SiO2 as an emulsifier and a modified additive for the storage stability of emulsified asphalt and the mechanism of difference.Both microscopic and macroscopic experiments have shown that nano-SiO2 as an emulsifier can make emulsified asphalt have better stability compared with nano-SiO2 as a modified additive.The research indicates that nano-SiO2 as an emulsifier can better solve the problem of insufficient stability of emulsified asphalt and has good application prospects.