Titanium alloy intermediate casing is a typical large casting, with many thin-walled and complex structures. It is a high cost and time-consuming process in the trial stage to manufacturing the wax pattern of the intermediate casing by metal mold. Rapid investment casting based on 3D printed patterns is the development direction of casting technology which integrates digitization and intelligence. In this study, selective laser sintering (SLS) technology was used to realize the rapid prototyping of polystyrene pattern in the precision casting of intermediate casing. A numerical simulation method was used to predict the filling process, solidification and casting defects of the intermediate casing. The simulation results show that the gating system for the casting of intermediate casting was reasonable, the number and size of gating risers met the open design requirements, and a sequential solidification of the casting could be realized. The titanium alloy intermediate casing with excellent metallurgical quality and size accuracy CT7 was successfully produced using centrifugal rapid casting technology.