<p>Investment casting is a widely used casting technology in which a wax pattern is formed by injecting molten wax into a mold. The dimensional accuracy and geometric precision of the wax pattern directly affect the quality of the castings. As investment castings often involve large sizes and complex geometries, controlling the wax injection process has become increasingly important and challenging. Therefore, understanding the mechanisms underlying wax pattern deformation and localized dimensional changes is essential for improving dimensional accuracy. Numerical simulation is an effective method for analyzing the wax injection process. However, the key challenge in using numerical simulations to analyze wax pattern filling is the lack of material property data for specific wax types. In this study, performance tests were conducted on F28-44B wax, and a material database was established in the commercial modeling software Moldflow. Numerical simulations were then carried out to investigate the wax injection process for the aero-engine cover by analyzing the temperature field, flow process, volume shrinkage, and warpage deformation of F28–44B wax. Since the simulated warpage deformation agreed well with the experimental measurement, the reliability of the commercial simulation was verified. The effects of different processing parameters on wax-pattern defects and deformation dimensions were examined, and an optimal combination of processing parameters for the aero-engine cover wax pattern was proposed.</p>