Currently, industrial robots are widely used in various fields, and the quality requirements of robot arm castings are also increasing. Based on the structural characteristics and technical requirements of the robot arm and combined with the characteristics of the iron mold sand covering casting process, the iron mold sand covering casting process scheme of the robot arm casting was designed, which was then optimized by solidification simulation software. The results show that the optimization scheme of the iron mold sand covering casting process for robot arm castings is feasible, which allows stable, efficient and clean production of castings to be achieved. The quality of the casting product is stable, with the qualification rate reaching over 95%, the surface roughness reaching Ra 12.5~25.0 μm and the dimensional accuracy reaching CT7, which reduces the production cost and can be popularized and applied.