Abstract: The variation between dimensionless liquid production index and water cut is the main basic parameters of reservoir productivity evaluation and lift mode selection for waterflooding oilfield. In the various research methods available many problems are existed and lack of percolation theory support for empirical method and numerical simulation method, and using relative permeability curve approach cannot determine the function between dimensionless liquid production index and water cut. This paper improves the relationship of oil relative permeability, introduces two types of relationships between oil-water relative permeability ratio and outlet end water saturation proposed by Dr. Yu Qitai, and establishes the models for their dimensionless liquid production indes and water cut, respectively. By comparison with the results from different oilfield in oil-water permeability experiments, it is concluded that Type II model is in accord with the experimental results, worthy of reference for other oilfields