Abstract: Abstract: As the core process of precision casting, investment casting plays an irreplaceable role in high-tech fields such as aerospace. As a key component of investment casting, the quality of ceramic shell directly affects the accuracy and performance of the final casting. Thermal stress is the main factor causing cracking and deformation of the mold shell, which in turn leads to casting defects. This article systematically analyzes the formation mechanism of thermal stress in ceramic shells during investment casting process, and comprehensively summarizes the methods of thermal stress control from four dimensions: material optimization, process improvement, structural design, and advanced control technology. In terms of materials, the selection of low thermal expansion coefficient ceramic materials, optimization of slurry formulation, and application of carbon fiber reinforcement technology were discussed in detail; The process control covers parameter optimization throughout the entire process of dewaxing, sintering, and pouring; At the same time, the application of numerical simulation technology and intelligent control systems in thermal stress prediction and control was introduced. Research has shown that by adopting a comprehensive control strategy, the thermal stress of ceramic shells can be effectively reduced by more than 30%, significantly improving the yield and dimensional accuracy of castings. Finally, prospects for future research directions were proposed, providing theoretical basis and practical guidance for the advancement of investment casting technology.