<p>The overlying soil layer exerts a significant impact on the seismic performance of pile foundations in liquefiable soil sites. In cold regions, the dynamic response of both the soil and pile foundation becomes intricate under the combined action of overlying frozen soil and liquefiable soil. This study employs an experimental method to investigate the seismic response of pile foundations in liquefiable soils with an overlying frozen soil layer. The analysis focuses on key parameters including pile strain, acceleration, and displacement of both the pile and surrounding soil, as well as pore water pressure in the sandy soil layer (liquefiable soil). During the test, liquefaction of the sandy soil layer initiates from the bottom and progresses upwards, and the liquefaction height increases as the ground motion intensity rises. The acceleration amplification coefficients of frozen soil and sandy soil are inversely correlated with the input ground motion intensity, indicating that the frozen soil can suppress the amplification of seismic waves. The peak horizontal displacement of the sandy soil layer is influenced by both the liquefaction height and soil elevation. Nevertheless, the impact of liquefaction on horizontal displacement is more pronounced than that of soil elevation. Moreover, the overlying frozen soil can enhance the bearing capacity of pile foundations in liquefied soil sites. Notably, abrupt strain changes are observed at the interface between frozen soil and sandy soil layers, as well as in the liquefied soil layer. These changes increase the vulnerability of pile foundations to seismic damage.</p>