During the drilling of carbon fiber reinforced polymer (CFRP), the defects, such as burrs and delamination, are prone to occur. The drill structure is a key factor influencing the formation of the defects. Two new drills are designed according to the existing novel drill bit. The thrust forces and the performances of these drills are investigated. The results show that the thrust force degradation rate of the existing novel drill bit in the trimming stage of the “V-shaped” cutting edges is the biggest, and that of the newly designed swallowtail-grooved drill is smallest. These change rules of the thrust force degradation rates are basically the same as that of the defects. Then, the changes of the thrust force degradation rates have good mapping relations with the regularities of the defects. The burrs can be effectively reduced by using these three drills. Compared with the existing novel drill, the burrs and the delamination can be more effectively reduced by the two newly designed drills. The main defects form of the existing novel drill is the tearing, but the main defects forms of the two newly designed drills are the delamination. This paper provided a new design idea for the tool structure design of CFRP drilling.