Electro-osmosis is an effective way to treat soft soil ground, and the determination of its basic parameters is important in practical applications. With a new laboratory device, two electro-osmosis experiments are performed on high-moisture clay under the conditions of steady voltage and current respectively, to measure the evolution of current, voltage and water flow rate through the clay specimens. The electro-osmotic parameters of the permeability coefficient, the migration coefficient, the electrical conductivity and the unit energy consumption rate are studied. It is found that in the process of the electro-osmotic experiment, the electro-osmotic permeability coefficient, the electrical conductivity and the unit energy consumption rate decrease gradually, while the electroosmotic migration coefficient is relatively stable. Therefore, it might be more reasonable to assess the electroosmotic efficiency with the migration coefficient.