Abstract: When Beijing-Zhangjiakou high-speed railway pass through the Guanting area, under the long-term traffic cyclic dynamic loading, the deep old cohesive soil will be deformed, which may affect the safety of high-speed railway operation. Focusing on this problem, GDS dynamic triaxial apparatus was used to study the dynamic characteristics of Guanting deep old cohesive soil, considering dynamic frequency, dynamic stress amplitude and consolidation stress. The results show that the strength of Guanting deep old cohesive soil is higher than that of ordinary mucky soil. For the same consolidation stress, the higher the dynamic stress ratio is, the greater development the dynamic strain is. The effect of low frequency load on dynamic strain is more obvious than the high frequency for the same layer. Under the same dynamic stress ratio, same frequency and different consolidation stress, the dynamic strain curves are divided into failure type, critical type and stable type. Soil with higher consolidation stress is more difficult to produce dynamic strain, and the less vibration required to reach stability. The research conclusions have reference value for the study of dynamic characteristics of deep old cohesive soil under traffic cyclic loading, and provide a reference for the settlement control of high-speed railway.