Abstract: It is significant for predicting the changing law of water cut with different development time in water flooding field.A model for predicting cumulative production was used for predicting the water cut based on the increasing law of water cut of water flood field,then a new model of predicting water cut for water flood oilfield was developed,and the model could be simplified into Logistic model.The model can be solved by the binary regression method,which was verified by using the actual water cut data of Shengtuo oilfield in Shengli and Shuanghe oilfield in Henan.By compa-ring with the predicting results of Logistic model and Gompertz model,it shows that the model is more accurate.So it can be use to predict the water cut of oilfield and guide the development of water flood oilfield.