Three cone bit is the important tool in oil drilling, whether its performance is good or bad will directly affect the quality of drilling, drilling efficiency and drilling cost. Three cone bit’s design in the traditional is based on practical experience and combined with the method of trial and error, repeated design and calculation, so the accuracy of design is low, the cycle is long and it is difficult to improve the quality of design. And the design of each calculation can only be a bit and with low efficiency. Therefore, to develop a set of three teeth wheel drill bit CAD system and realize parametric drawing of three cone bit are very necessary.