Abstract: During later high-water cut stage of oilfield development, the conditions of production pressure and flooding pattern were basically unchanged, production must decrease in accordance with the law of declining. The type of water flooding declining in Sazhong oilfield is in line with the index declining model, which can only predict oil production, cumulative oil production and recoverable reserves, it can't predict the water cut, water production and liquid production of water flooding oil field. If combining index declining model with Type C water flooding featrue curve, we will predict more development indexes in water flooding oil field. As tertiary infill wells have been put into production for not a long time, the production havn't declined yet, the recoverable reserves of the infill wells can be predicted using the expirical relationships between flooding recovery and well density first, and then predict the development index with the combined solution of generalized Weng's model and Type C water flooding featrue curve.