Abstract:This work mainly analyzes and summarizes the observation data of four geoelectric field stations in Jiangsu Province from 2015 to 2019 subjected to interference by national high-voltage direct current (HVDC) transmission lines. The influence characteristics and data interference magnitude of the Xitai, Jinnan, Jinsu, and Changxuan lines are mainly considered. The conclusions are as follows. (1) The interference of the HVDC transmission lines with the geoelectric field observation data is a far-field interference. Under the interference of the same HVDC transmission lines, the range of the change ratio of the observation data at a long polar distance and short polar distance of the same station in the same direction is close to 1. (2) The forms, directions, and ranges of the data change of different stations caused by HVDC line interference differ in terms of station location, HVDC converter station location, relative position of ground electrode, and underground transmission medium. The results can provide a reference for the discrimination of geoelectric field observations disturbed by HVDC transmission lines. They may also be applied to geoelectric field observation data.