Abstract: The resistivity of the water flooded zone decreases significantly after saline water flooding occurs in the oil zone. How to accurately identify the water flooded level is critical to evaluate the water flooded zones. The resistivities of oil-saturated and water-saturated zones can be obtained from the inversion of variable multiple material balance model. In the study area, the resistivity value of the water flooded zone falls between those of oil-saturated and water-saturated zones, and the lower the water flooded level is, the closer the formation resistivity goes to that of the oil-saturated zone; on the contrary, the higher the water flooded level is, the closer it goes to that of the water-saturated zone. The change rates relative to the resistivities of oil-saturated and water-saturated zones are used to establish a detailed interpretation chart for water flooded zone and quantitative classification standards for water flooded level. The actual application shows that the interpretation accuracy of saline water flooded zones has reached 88.8% and the resistivity inversion technology lays a foundation for logging evaluation of saline water flooded zones in Weizhou oilfield.