The classical traction network impedance calculation formula use the solid circular wire model and the Carson series method, but it is based on the power frequency (50 Hz) during the derivation process, which is not suitable for high frequency calculation. In order to accurately describe the high-frequency impedance characteristics of the traction network, the hyperbolic cotangent approximation and the Sunde ground impedance calculation method are used to summarize the calculation formula for the high-frequency impedance of the traction network. Combined with the scientific calculation and simulation of Python, the traction grid of the power supply arm of the east section of Shanghai-Nanjing Wuxi Substation is used as an example, and the relationship between the high-frequency impedance of the traction grid and the erection height and earth conductivity is analyzed. The results show that the conductivity and height of the earth have little effect on the impedance value under low frequency currents, but the effect of the earth conductivity and erecting height on the impedance of the traction network at the high frequency, especially when the frequency is higher than 10⁴ , cannot be ignored. In the simulation of high frequency or fast transient, the values of ground conductivity and erection height need to be accurate.