Resin film infiltration (RFI) process is a widely used integrated manufacturing technology in composite material molding, which is very suitable for manufacturing large, reinforced, and complex aviation structural components. This article selected a typical composite hat stiffened panel, completed the integrated design of the fixture structure and process flow, and simulated the resin penetration process under different resin film positions and curing pressures. Based on the simulation results, reasonable resin film positions and curing pressures were selected. Finally, process experiments were completed according to the selected scheme, and the apparent quality and non-destructive testing of the typical parts were qualified, verifying the effectiveness of RFI integrated design and  simulation analysis for hat stiffened panel.