In order to offer theoretical basis for the vibration prevention and noise reduction for the area along urban rail traffic line, the propagation laws of environmental vibration are summarized by analyzing observation data in time and frequency domain based on actual field observation data in Beijing. The mathematical statistics method under the criterion of least-squares has been used to study the vibration propagation and to establish the empirical formula of vertical ground vibration. The results obtained from the empirical formulas proposed agree with the results of field observation well. The vertical ground vibration level is much higher than that of horizontal. So the vertical ground vibration level is the most important aspect when evaluating ground environmental vibration level. The field response near the rail depends on the high frequency vibration caused by moving train and that far from the rail is dominated by the natural vibration frequency of train and the field vibration. The response amplitude of environmental vibration would be changed when load changed.