In the process of CNC cam grinding,the contact point of cam and grinding wheel may not be on the line that connects the two components.The contact point may be shifted during the process of grinding,contour asynchronization may happen between the original cam and the processed one if the original contour data of cam are still used directly.The relation between the radius of grinding wheel and the offset was studied,the disadvantage of using curve fitting to determine the contact point was analyzed,and a new algorithm to determine the contact point directly from the discrete data was given and proved.Compared with the curve fitting-based methods,the algorithm can be easily implemented by using computer program,and is more applicable.The experiment results show that the algorithm can effectively eliminate the influence of the radius of grinding wheel on the cam contour,and the cam produced can be wholly identical to the original cam.