Abstract: In treatment of soft soil foundation by electro-osmotic drainage, to explore the electrode conversion cycle, the equal-time and equal-drainage-volume electrode conversion tests are performed by using a new kind of corrosion-resisting EKG drainage board. In the former test, unit soil is given as the model, change of currents and displacement is observed, and equal-time electrode conversion is proved to be not conducive. Rectangular shaped soil is regarded as an one-dimensional model and equal drainage volume is controlled by switching electrode in another parallel test, where electrode conversion time and cycle are recorded for numerical fitting, and an exponential curve fitting is revealed. In the same way, ideal electrode conversion cycle law and analogous drainage volume can be easily got by iron, but the iron cannot afford long-time electro-osmosis because of corrosion. Finally, by measuring the soil moisture content and electric conductivity after electrode conversion and conventional electro-osmosis tests, distribution diagrams of soil moisture content and electric conductivity are compared. It’s found that the equal-drainage-volume electrode conversion test by EKG drainage board can obtain processed homogeneous soil, which can provide reliable experimental basis for the application of EKG drainage board instead of iron in the electric field.