Due to the special structural materials， long history and rich cultural connotation of ancient buildings， their dynamic response law under traffic vibration has become an important research content of ancient building safety. Aiming at the vibration elevation effect of the ancient city wall under the influence of road vehicles and the safety evaluation of the structure， based on the field test of vibration characteristics under various working conditions and the theoretical analysis of vibration elevation response mechanism， combined with the method of numerical simulation， and according to the corresponding safety criteria and allowable standards， the research is carried out. The results show that the main frequency range of vibration of the ancient city wall under the influence of road traffic load is 5~25 Hz， the vibration speed of the top of the wall is larger than that of the bottom， and the amplification coefficient of the top is 1.08~2.21. The amplification effect of vibration is mainly affected by the load and speed of vehicles.With the increase of simulated vehicle load and driving speed， the peak velocity amplification coefficient fPPV of the wall particle increases， and the vibration amplification effect is obvious，fPPV is between 1.02 and 1.77. The analysis of incremental ACI of fPPVshows that the effect of vehicle load on vibration elevation is greater than that of vehicle speed. By fitting the simulation results and the field measured data， it is found that there is a certain linear relationship between the vibration velocity at the bottom and the top of the wall under the excitation of traffic vibration. According to the field measured data and numerical simulation results， the safety of the ancient earth wall is evaluated， and the anti-vibration measures of the ancient earth wall based on the traffic management of passing vehicles are proposed.