In this paper, aiming at the lateral low-frequency swaying of a high-speed locomotive body, a suppression method is proposed to replace the traditional anti-hunting damper by a frequency-selective-damper (FSD) . Firstly, the dynamic model of the locomotive is established by Simpack, and the characteristics of lateral low-frequency swaying of the car body are analyzed think distribution of the car body vibration. The analysis shows that the lateral swaying frequency of the car body ranges from 1 to2, being distinguished from other lateral vibrations. Then, the CFD model of frequency valve and the numerically simplified model of FSD are established. Finally, the results of lateral vibration of vehicles with traditional yaw damper and FSD are compared in frequency domain. The results demonstrate that a FSD damper instead of traditional yaw damper can significantly improve carbody hunting stability and reduce the amplitude of low frequency swaying of the locomotive due to the lower damping coefficient in low-frequency condition. At the running speed of 160km/h, the peak values around the main frequency of lateral acceleration and yaw acceleration decrease by 42% and 37.5% , respectively effectively reducing the low-frequency sway of the locomotive.