The railway passing through the loess soil area is prone to settlement under the long- term action of train load. In this paper, the distribution characteristics and dynamic characteristics of loess soil in southern Hebei are studied.Methods:In this study, through investigations and indoor geotechnical tests ，the distribution characteristics of loess- like soil in southern Hebei were proved.andthe physical and mechanical properties of different types of loess- like soil were tested. On the basis of field investigation and indoor geotechnical test, single- sample multi- stage loading and parallel multi- constant amplitude dynamic loading tests were carried out on the medium collapsible loess-like soil mainly passed by the railway by using dynamic triaxial tester. The deformation and failure characteristics of loess soil under different consolidation ratio, confining pressure, dynamic stress, vibration frequency and collapsibility grade were studied.Results: The main achievements are as follows: ① The degree of collapsibility of loess- like soil in the eastern plain in southern Hebei is slight to moderate, and the local area is strong. The degree of collapsibility of collapsible soil in western region and piedmont platformis strong, and the coefficient of collapsibility is 0.14. ② The dynamic stress is an important factor affecting the deformation of loess- like soil. There is a critical dynamic stress value when the soil is damaged. When the dynamic stress is less than the critical value, the sample hardening phenomenon occurs. After exceeding the critical value, the sample softening phenomenon is significant. ③ When the train load is the same, the higher the speed of the train, the smaller the strain of the soil but the increase is reduced. ④ The critical dynamic stress ratio of loess soil decreases with the increase of collapsibility coefficient, and the critical dynamic stress ratio decreases obviously compared with that of non- collapsible soil.Conclusions:The research results have reference significance for the prevention and control of roadbed disasters in urban rail construction in loess soil areas and the research in related fields.