This paper studies the characteristics of ground vibrations due to underground trains and their transmission laws.The study consists of the simulations of the train-track system vibration,which provides the excitation loads of moving trains onto the tunnel structure,and the calculation of the track tunnel-ground system vibration,by which the transmitting properties of ground acceleration and velocities are studied.The main results include 2 aopectcs:vibration amplifying area exists certain distance away from the tunnel centre,and thedominant frequencies of the ground vibration concentrate to a certain band.Buildings that locate in that area and whose resonance frequency
drops into that frequency band would be greatly influenced by the underground train-induced vibration.