The heterogeneity of the reservoir of Ordovician systemin Tahe Oilfield is serious, and the water-oil relation is complex, water breakthrough in the oil well is the main reason that causes production drawdown. The sources of the water body in the water breakthrough well include the leakage fluid and the acid fracturing fluid remained, relic water in the bottom of the fracture-cave unit. The water body in the lower part of the fracture-cave unit is connected by acid fracturing. The output of the leakage fluid always presents the pattern of water cut decline which has low influence on the production. The output of the relic water and the water body in the lower part are different because of the energy of the water body, the height of the oil-water contact and the difference of the vertical permeability. It is a effective way to enhance the ultimate degree of reserve recovery in the reservoir that take steps to stabilize oil production and control water cut of the different resources of the water body and different characteristics of water breakthough.