The dynamic response law of pile foundations on liquefied soil is a perennial hot topic in the field of earthquake resistance engineering. In this work, the lateral dynamic response characteristics of pile groups in a nonliquefied soil layer and saturated sand layers with two different thicknesses are studied under the input of a sine wave with a certain peak acceleration and frequency through the model shaking table tests of 2×2 pile groups. Results show that under the input of the sine wave, the time histories of acceleration and displacement at the pile cap in nonliquefied sand are not significantly different from those of the input. The peak acceleration and peak displacement at the pile cap drastically increase in saturated sand with two different thicknesses. Specifically, the peak acceleration and peak displacement at the pile cap are magnified by 1.83 and 1.58 orders, respectively, in thin saturated sand, and by 2.18 and 1.91 orders, respectively, in thick saturated sand. Under the same input condition after liquefaction, the dynamic response of the pile cap is more remarkable in thick saturated sand than that in thin saturated sand.