Abstract: The orbiting scroll is one of the core components of a scroll compressor, its complex structure is prone to casting defects, and it is difficult to obtain samples for mechanical property testing of thin-walled sections. Therefore, employing numerical simulation technology to study its casting defects and mechanical properties can provide valuable insights for addressing these challenges. Taking the QT450-10 orbiting scroll as the research object, this paper conducts a numerical simulation on its casting process by adopting sand mold casting technology combined with ProCAST software. A finite element model is established to analyze the filling and solidification processes in the casting procedure, predict shrinkage cavity and porosity defects, as well as the distribution rules of tensile strength and hardness of the casting. The predicted results are further compared and verified with actual production data. The research results show a good agreement between casting defect prediction and production verification, with consistent variations in the predicted and measured tensile strength and hardness values at critical locations of the castings