To gain a better understanding of the deformation behavior of Jiaxing Quaternary sedimentary soils, we collected total 34 undisturbed soil samples. The analysis results revealed that the variation characteristics of the normalized dynamic shear modulus ratio (G/G_max) and damping ratio (λ) with increasing shear strain (γ) are strongly influenced by the sedimentary facies and geological time. For the same sedimentary facies, the more recent the geological time, the larger is the dynamic shear modulus ratio and the smaller is the dynamic damping ratio. For the same geological time, we found the dynamic shear modulus ratio of the alluvial-lacustrine deposit to be largest, and the dynamic damping ratio the smallest. Moreover, we suggest recommended values for the dynamic shear modulus ratios and dynamic damping ratios of soils of different sedimentary facies and geological time in Jiaxing area. Furthermore, we used FLAC^3D modelling software to perform a dynamic response analysis of the soils at one typical engineering site using the recommended and measured values and verified the applicability of the recommended values. These study results can be used as reference in the seismic risk assessments of engineering projects.