PDC drill design of high-quality three-dimensional model requires a wealth of expertise and skills in three-dimensional design tools, and it is a highly intelligent and complex process. This paper presents the basic model of drills combined with expert design knowledge to form a PDC drill intelligent design system. The system selects basic model of drills according to stratum properties, and then specifies various blade curve constrained by drill criteria. At last, the system optimizes drill parameters to build up three-dimensional model through expert knowledge base. PDC drill of intelligent design system combines expert design knowledge and the drill design criteria, with intelligent, simple operation and high accuracy features.