Abstract: In order to investigate the temporal and spatial characteristics of physical properties of sand, the studies on electrical resistivity properties of saturated sand with varied porosities should be carried out primarily. Firstly, the resistivity measurement devices are developed by using the two-electrode AC electrical method, and the reliability of the devices is verified by considering the effects of electrifying time and contact resistance. Using the devices, the electrical resistivities of sand under varied effects of resistivity of pore water, saturation and porosity of sand are studied. And the resistivity of saturated sand varing with the porosity is highlighted. The results show that the effect of conduction history can be ignored using the devices, and that the contact resistance between electrode and soil is remarkably related to the saturation of sand. The influences of the resistivity of water, saturation and porosity of sand on the resistivity of sand have a decreasing order. There is a remarkable power function between the resistivity of saturated sand and its porosity. Their influence sequences on the resistance of sand are sorted by the noise-signal ratio and range analysis.