Water flooding performance evaluation and recovery prediction with relatively easy tools has always been among the top aims of reservoir engineering studies, especially for mature reservoirs in high water-cut period. Relative permeability curves are basic required properties reflecting multi-phase flow characteristic and used together with production history to evaluate reservoir performance. In high water-cut period the relative permeability ratio deviate from the empirical straight-line form, which makes traditional models less effective or erroneous in performance prediction. This paper presents a new relative permeability ratio model which can convert the non-linear characteristic of this problem into linear expression. And a new simple water flooding performance analysis technique is developed based on the new model, which can be used to forecast ultimate recovery factor and the corresponding sweep efficiency. The main advantage of this work is taking into account of high water-cut characteristic with less model parameters compared with other improved models. Synthetic case and field examples demonstrated the advantages of this method in parameter solving and consistency in history matching. The proposed technique in this work can be used as predictive analysis tool in forecasting ultimate recovery and performance evaluation for mature water flooding reservoirs.