Abstract: On the basis of the definition of net injection percent and water flooding index,combined with the dimensionless injection and the dimensionless producing formula to establish a mathematical model reflecting the variation of net injection percent and water flooding index with the recovery percent of reserves,and through drawing the changing relation curves of the actual interval net injection percent and the water flooding index of Sabei oilfield,we analyzed the changing characteristics of the net injection percent and water flooding index during different stages of development in Sabei development zones,evaluated the water injection devel-opment results of Sabei development zones,meanwhile discussed the effective ways of Increasing net injection percent during the later high water cut stage so as to adjust the water flooding structure.