Abstract: Experimental study indicates that,for super- low permeability cores from oil field in western,the relative permeability curves are characterized by high in - educible water saturation,low remaining oil saturation and wider two -phase region.The relative permeability curve patterns of wa- ter phase have 2 types,which is the straight line and upward concave.The relational expression of the oil - water relative permeability ratio and water saturation is exponential model, and the displacement characteristic of the water-drive curve is the first water drive characteristic.