Abstract: Anpeng oilfield is characterized by tight and low permeability reservoirs, poor reservoir physical properties, high seepage resistance and low natural productivity. Through conventional vertical wells for production, the initial production capacity is low and the production decreases rapidly. Based on the understandings of geological characteristics of Anpeng deep reservoir, considering the impact pressure gradient and reservoir stress sensitivity of tight sandstone reservoir, a large reservoir numerical simulation model was established to optimize the parameters, such as fracture numbers, fracture length and fracture conductivity of horizontal wells. At the same time, "unequal length distribution of fractures" and "unequal injection" were adopted to reduce the risk of water breakthrough in injection-production well pattern of horizontal wells, and finally the reasonable design parameters and pattern of horizontal well fracturing were obtained. The results show that the optimized well pattern not only obtains higher productivity but also delays the water breakthrough time of horizontal wells, which greatly improves the development effect of fractured horizontal wells.