A transformation technology for part model to blank model based on feature mapping of turbine blade was prompted to improve the design efficiency of investment casting mold. The definition, feature presentation and feature mapping theory were researched. The feature and the geometry structure of turbine blade’s part mold, blank model and cavity mold were analyzed, and the feature mapping technology was prompted. At last, a mold transformation system was developed based on UG. Experiment result shows that with the help of this system, designers can improve design efficiency of investment casting mold of turbine blade.