Abstract: The dynamic behavior of the frozen clay obtained from subgrade of Beijing-harbin Railway in northeast of China is investigated through cryo-dynamic triaxial experiments. The effects of several key factors including temperature, frequency and freeze-thaw cycles on the dynamic behavior are analyzed. Conclusions are drawn as follows: the reciprocal of dynamic shear modulus and dynamic strain is obviously in linear relationship. The dynamic stress-strain curve can be described by the Hardin-Drnevich hyperbolic model perfectly, and with the decrease of negative temperature and the increase of frequency the dynamic stress-strain curve are steeper. Freeze-thaw changes the structure of soils, the dynamic stress-strain curve is greatly different from that passing the first freeze-thaw cycle, and with the times of the freeze-thaw cycles, the property is steady.