HVDC transmission faults, geoelectric storms, geoelectric resistivity observations, artificial power supplies, and subways usually interfere significantly with geoelectric field observations, thus causing great trouble to the application of observation data and the extraction and identification of seismic anomaly information. Thirteen geoelectric field stations with good observation systems, such as Lingyang and Guazhou stations, were selected for analysis in this paper. Based on the seepage(movement)model of rock fissure water (charge) in the telluric field, the change of dominant azimuth α of the telluric field at each station under typical interference was calculated. Results show that the effect of usual interference on the calculated value of α is not obvious. However, severe interference with large amplitude lasting for many days may have impacts on some sites. The analysis results of the Ningqiang MS5.3 earthquake in Shaanxi Province on September 2018 show that the anomaly of α in the surrounding sites may be remarkable before a strong earthquake under complex conditions. The results of this research may have some reference significance for the application of geoelectric field data.