The control of settlement after construction of subgrade for high speed railway is a difficult problem, and the study of dynamic load is still in the stage of numerical calculation and experiment. Therefore, relying on the construction and operation monitoring data of Shanghai-Nanjing intercity railway, test values of settlement under the action of dynamic load are used to analyze the settlement characteristics caused by dynamic load based on the method of separating the settlement caused by static and dynamic load. The results show that settlement caused by dynamic load has limited contribution to the operation data of the settlement, while it is not the main reason causing settlement large. Different geological conditions and construction of embankment height have little influence on the settlement caused by dynamic load. Settlement rate caused by dynamic load is faster and reaches the maximum in the early development of the operation, then gradually decreases. The settlement tends to be stable after operation four years is about 2~3 mm.