Abstract: Different methods have different applicability, and a single test is not a full, objective, realistic way to reflect the operating state of the switchgear. Transient Earth Voltage detection has been widely promoted in the regular testing of the switchgear by virtue of the advantages of non-power failure detection, high sensitivity, strong anti-interference ability and non-invasion, etc. However, the research on the detection mechanism, influencing factors and propagation characteristics of TEV method is still in its initial stage. On the basis of theoretical analysis of partial discharge transmission characteristics and influencing factors, established the finite element model of the switch cabinet and deduced the TEV transmission characteristics and relationship between partial discharge source and its influenced factors. The conclusion was confirmed by using the online measured TEV data.