Abstract: The quantified relationship between relative permeability and saturation is the key dynamic parameter relationship of multiphase flow system in porous media.Under the dynamic condition,the designed apparatus and method are employed to measure the relative permeability and saturation in wateroil twa-phase system.The experiment was conducted in a one dimension sand column and the results were analyzed.It indicates that the results measured by the apparatus are in acrd with those in practical condition.The fine sand is hydrophilic,which remarkably affects the relative permeability and saturation of water oil and causes the displacement mechanism difference of different fluids in different firstly wetting conditions.The oil-water phase saturation is the main influential factor of phase relative permeability,and the viscous difference of different fluids affects the relative permeability.And the relative permeability should be determined by the liquids distribution in porous media and the saturation history of fluids.The experimental data are very well fitted in with the VGM model (or the Parker-Lenhard model).At the same time the parameter in fitting capillary pressure-saturation data using the van formula is transferred in predicting relative permeability-saturation curve with VGM model in the water firstly wetting condition.And the result is compared with that of direct fitting of the relative permeability-saturation data by the VGM model,which suggests the latter model shows a better performance.