The temperature field and stress field of a thin-walled complex titanium alloy casting was simulated by numerical simulation technology, and the casting process suitable for the casting was determined. The temperature field distribution simulated by the scheme is relatively uniform, which is conductive to the balanced solidification of the casting. Internal quality reaches optimal, and the simulated stress field distribution is relatively uniform with the lowest stress difference in the whole casting. According to the simulation results, riser feeding is adopted for the parts with large wall thickness radio. High quality castings which are consistent with the simulation results and meet the technical requirements are effectively produced by optimized casting process.