Abstract: In order to study the dynamic response of loess slopes under high-speed train loads and evaluate their influence on the stability of the loess slopes, the vibration characteristics of loess slope site under train loads are analyzed in time domain and frequency domain, then the site effect of the loess slopes is analyzed.The results show that the acceleration and vibration acceleration increase in different stepped loess slope sites when different speed trains pass.The vibration frequency at each measuring point is mainly concentrated in the range of 10~80 Hz, the distribution of the main frequency at each measuring point is obviously different, and that when the train passes through the same measuring point at different speeds is also very different.The time-frequency curve is stable during 2~5 s and no abrupt change occurs, which indicates that the train runs at uniform speed.The spectral curve shows a abrupt peak between 0~2 s and 5~7 s, which indicates that the running state of the train has changed.