Abstract: The lack of land promotes the application of electro-osmosis reinforcement in soft clay foundations, but insufficient attention is given to its design method. Electro-osmotic process and electrodes electrolytic reaction are studied based on the electro-osmotic mechanism. The influences of four different kinds of factors on the electro-osmosis are analyzed, including soil properties, electrode, power output and power modes. An electro-osmotic design method for soft clay foundations is proposed based on the existing cases and illustrated by an example. The proposed method can be applied in the electro-osmotic treatment of common metal electrodes arrayed in  rectangle and in other conditions after simple modifications. It has the abilities to evaluate electro-osmotic treatment suitability of sites, to consider the influence of site geological conditions and to improve the efficiency of electro-osmosis by controlling the parametric values.