Abstract: Most oil fields are in the subordinate phase of production with high water-cut, the distribution of oil and water is more complex, so it is more difficult to select well or layer to fracture, and the geology conditions of reservoir to be fractured is more worse. Therefore it is necessary to improve pertinence of fracture project design to fracture more effectively. Mathematical flow models of reservoir and fracture as well as optimization model were established in this paper, using reservoir numerical simulation method, calculated the production performance after fractured, the fracture parameters(ration of fracture length to distance between wells) are optimized according to the germinal added oil volume and cumulative add oil volume. The calculated results show that the results are different for different layers if the optimization object is different, even for the same layer, if the optimization object is different, the calculated results are different.