As a commonly used method to reinforce slopes, prestressed anchor cables can effectively prevent slope instability. To study the dynamic response characteristics of loess slopes reinforced with prestressed anchor cables under earthquake action. Taking a slope in Yan'an as an example, using MIDAS/GTS numerical simulation, a model of loess slope reinforced by prestressed anchor cables under earthquake action is established, and the dynamics are analyzed in terms of slope displacement, horizontal and vertical velocity, maximum principal stress, and anchor cable axial force. Based on the response characteristics, the influence of peak seismic acceleration and ground motion duration on the stability of loess slopes is analyzed. The results show that under the action of an earthquake, the range of displacement and velocity of the slope surface is larger than that of the inside of the slope, and the slope surface is more prone to instability. The seismic wave has little effect on the axial force of the anchor cable at the same elevation. The displacement of the slope increases with the increase of the seismic peak acceleration, and the input peak acceleration is every time With an increase of 0.1g, the deformation at the slope surface S5 increases by 0.014m, and the slope displacement changes significantly with the change of the duration of the ground motion, increasing continuously.