The multi-facet drill shows good performance during materials are difficultly machined. However, for a new type of the drilling point, the grinding has been the main problem that restricts its application. To properly grinding the drill point confirms the design parameters, the relationship between design parameters and grinding parameters must be resolved. The mathematical model is the key to solve this problem. In this paper, according to the design of the high manganese steel drilling tool, a mathematical model has been established by the plane grinding method to solve grinding parameters, and to achieve improved mechanical grinding of drill point.