One-dimensional site response analysis is a widely adopted method for assessing seismic response in nuclear power applications. To ensure the reliability of the analysis in practical engineering projects, it is essential to conduct a sensitivity analysis of key parameters. In this study, typical clay and sandy soils are selected as foundation parameters, based on the geotechnical properties of existing and potential nuclear power plant (NPP) sites in China. The effects of three key factors on peak accelerations and acceleration response spectra are investigated. Based on the results of the sensitivity analyses, the following conclusions are drawn: (1) Variations in soil layer thickness have a minimal impact on the surface response spectrum. However, the thickness of the soil layer must be constrained by the shortest wavelength limit, particularly for soils with low shear wave velocities. (2) For five different levels of peak ground acceleration (ranging from 0.1 g to 0.5 g), the corresponding acceleration-depth curves shift in parallel. As peak acceleration increases, the ground response spectrum exhibits an overall upward shift, indicating a consistent amplification trend. (3)The shear strain of the soil significantly influences the seismic response. Results from different nonlinear soil models show considerable variation. However, the shear strain within the soil remains relatively constant, with no significant changes in magnitude when the seismic excitation level remains unchanged.