In order to study the viscoelasticity of the hydrophobic nano-silica modified asphalt and its mixture, the hydrophobic nano-silica obtained by surface modification of silane coupling agent was used to modify the asphalt. Penetration test, rotational viscosity test, shear rheological test and static creep test were carried out on the modified asphalt and modified asphalt mixture. The penetration index, rotational viscosity, complex shear modulus, elastic shear modulus, viscoelastic modulus, phase angle, rutting factor, strain difference and Burgers viscoelastic parameters were evaluated for viscoelasticity. The results show that the incorporation of hydrophobic nano-silica can enhance the viscoelasticity and high-temperature stability of asphalt mixture, and improve the temperature sensing performance of asphalt and the thixotropy under normal temperature. According to the main curve analysis, in the low frequency region, the incorporation of hydrophobic nano-silica can improve the phase angle of the asphalt and enhance the elastic property of the asphalt. By analyzing the Burgers model parameters of hydrophobic nano-silica modified asphalt, it is found that the incorporation of hydrophobic nano-silica can improve the viscosity of asphalt. The results of static creep test show that the incorporation of hydrophobic nano-silica can significantly reduce the strain value of the asphalt mixture at the same temperature. In addition, the incorporation of the hydrophobic nano-silica modifier can enhance the elastic portion of the asphalt mixture, increasing viscous flow deformation and viscoelastic delayed deformation.