Based on the apparent electrical variations anomalies in some typical earthquake examples, the relation between apparent electrical variation anisotropy and maximum principal stress from focal mechanism is introduced, the physical mechanism of this variation is discussed. 依据典型震例中的视电性异常变化,介绍了视电性变化各向异性与震源机制解最大主压应力的关系,讨论了电性变化的物理机理。