At present, the problems that need to be solved urgently in CFRP drilling are delamination and tool wear, which are closely related to the distribution of cutting force on the cutting edge. The aim of this paper is to present a method to analyze the cutting force distribution on the main cutting edge of the drill. This method applies to the analysis of the drilling performance of double point angle (DPA) drill and to optimize the step drill structure for CFRP drilling. Both of these applications prove the correctness of the analysis method. According to the calculation model of the rake angle of the main cutting edge of the twist drill and the cutting force prediction model, the distribution model of the cutting force on the main cutting edge is established. This method reveals the basic reason why the thrust force increases linearly when a single main cutting edge cuts into the workpiece. In the process of analyzing the drilling performance of the DPA drill, the edge force coefficient is used to represent the thrust force, and the application environment of the drill with a different structure is analyzed. Based on the distribution characteristics of the axial force on the main cutting edge, the step ratio of the step drill is optimized. This method can optimize the step ratio of the step drill. This method can be employed to optimize the step ratio of any structure step drill.