With the increase of train speed, the frost hazard of subgrade engineering in seasonally frozen soil becomes more and more serious. In order to research frost heaving characteristics of fine-grained soil subjected to dynamic loading, the frost heaving tests are performed. Based on the results of laboratory experiments on open frost heaven for fine-grained soils, the influences of no load, static load and dynamic load on frost heaven susceptibility are discussed comparatively. The test results show that the frost of soils is restrained respectively by the static loading and the dynamic load of a train. The frost heaving ratio of fine-grained soil gradually tends to reduce with the increase of external load, and when the static load is equal to half of the dynamic load, the characteristics of frost heaven of fine-grained soils under static load and dynamic load respectively are approximately equal. The moisture inflow velocity of freezing soil increases with the decrease of cooling temperature, and decreases with the increase of the dynamic load, The frost heave of soils is not affected by the change of cyclic loading frequency of the train.