Abstract: The electrical resistivity of the remold expansive soils was studied and a pseudo-electrical resistivity model of the saturated/unsaturated soil was presented.It was demonstrated that the electrical resistivity of remold expansive soils was a function of the electrical resistivity of soil skeleton and pore water,water content,degree of saturation and void ratio of soil,etc.The volumetric ratio of water in the soil,defined as the ratio of the volume of water in the sample to the total volume of the sample,was used as the controlling parameter.The relationship of matric suction-ratio of water volume was observed to be similar to the electrical resistivity-ratio of water volume.The measurement of the electrical resistivity method was shown to be satisfactory for investigating the behavior of expansive soils.Because the method was relatively easy to be used,it was actually advantageous.