Abstract: It is the key to ensure that PDC bit has choiceness of the work performance to reasonably place cutting.Presently common means of PDC bit placing cutting is to draw and adjust the scheme.But we have slow speed,poor efficiency to use the way and the designing work is also boring.What's more,unnecessary errors often occur.This paper narrates the principle and the way of the design for PDC bit placing by CAD,and introduces the contents and the elements of the Computer aided design.