Grounding resistance measurement is a necessary means to check whether the grounding device can meet the requirements of the regulation. It can avoid the economic loss or accident caused by grounding fail-ure timely. Due to the presence of mutual inductance between the leads

the measuring signal can be inter-fered

thereby affecting the measurement results. Based on this

the article firstly analyzes the influence mechanism of the mutual inductance between two parallel lines

and derives the additional resistance R caused by the influence of mutual inductance on the line. Then

due to the influence of mutual inductance with the change of the lead angle

the influence of mutual inductance can be converted into the effect of different angles on the measurement results

and the optimal angle value can be calculated by mathematical operation. Finally

setting up the experimental platform and carrying on the experimental verification. The results show that the mea-surement error can be minimized when the angle between the voltage pole and the current pole closes to 30 °

which is beneficial to the analysis and improvement of the measurement accuracy of the grounding resistance tester. At the end of the paper

a briefly analysis is made on the methods of the ground resistance measurement treatment in the case of non-uniform soil.