After large-scale fracturing of shale reservoirs，the shape of hydraulic fractures，the complex seepage mechanism after fracturing，and the interaction among multiple action mechanisms are the keys to the prediction of post-fracturing productivity and the deployment of shale gas well patterns. Based on the workflow of geology-engineering integration，the hydraulic fracturing network modeling and numerical simulation of shale reservoirs were carried out to optimize development technology policies and maximize economic benefits. The hydraulic fracture propagation model was built to simulate the post-fracturing network. The model considered the stress shadow between hydraulic fractures，natural fractures，in-situ stress，and the heterogeneity of fracturing fluid flow，ensuring that the simulated hydraulic fractures agreed more with the field reality. On this basis，post-fracturing numerical simulation was performed，considering complex gas seepage mechanisms. The research results show that the horizontal stress difference coefficient is small in the well area DP2 of the Nanchuan block，and hydraulic fracturing can produce a complex fracturing network. Hydraulic fractures are effectively supported in the lateral direction，and there is room for further improvement in productivity in the vertical direction. In light of stress sensitivity and economic benefit evaluation，the optimal production system is determined to be 6×104 m3/d，and the reasonable length of the horizontal segment is 2 000 m.