The structure optimization design for six kinds of typical investment casting parts was conducted based on the principle of six “by hook and by crook”, and CAE software was employed to verify the optimized effects. It is found that some defects encountered in the parts can be eliminated, including scab, inflation, bleeding from parting, shrinkage porosity, crack, by reducing large end face, and by avoiding deeply-long channel as well as using reinforced ribs, which improved the quality of the investment casting parts.