对北京、上海、深圳、无锡等4个城市监测的地铁动态直流干扰下埋地管道管地电位数据进行了系统分析，统计了不同城市地铁杂散电流干扰下管地电位的波动周期、周期分布、波动幅值等动态特征，分析了管地通电电位对断电电位的影响，总结了地铁杂散电流干扰下管地电位动态波动规律。结果表明：在地铁运行时段，管地通电电位波动剧烈，波动存在周期性变化；同一城市内不同监测点管地通电电位波动周期分布比例基本相同，不同城市的分布比例相差不大；各地的通电电位波动范围不同，受干扰程度也不同；管地通电电位与断电电位的波动周期相一致，管地通电电位的波动对断电电位存在较小影响。

The pipe-to-soil potential data of underground pipeline under dynamic DC interference caused by subways and monitored in Beijing, Shanghai, Shenzhen and Wuxi were analyzed systematically. The dynamic characteristics such as fluctuation period, period distribution and fluctuation amplitude of the pipe-to-soil potential under the disturbance of subway stray current were calculated in different cities. The effect of pipe-to-soil switch-on potential on switch-off potential was studied, and the law of pipe-to-soil potential fluctuation dynamically caused by the stray currents from subways was summarized. The results show that in the running periods of subways, the pipe-to-soil switch-on potentials fluctuated drastically, and the fluctuations were periodic. The distribution proportions of fluctuation periods of the pipe-to-soil swtich-on potentials were nearly the same for different monitoring points in the same city, and were similar for different cities. The fluctuation amplitudes and interference degrees of pipe-to-soil potentials were different in different cities. The fluctuation periods of pipe-to-soil switch-on and switch-off potentials were coincided, and the fluctuation of switch-on potential had a small effect on switch-off potential.