Abstract: Carbon fiber reinforced plastics (CFRP) have the characteristics of low interlayer strength and complex anisotropy, which are prone to machining damage. The selection of cutting parameters has a great influence on the quality of drilling. The finite element software was used to establish a machining simulation model for drilling T300 carbon fiber reinforced plastics, and different cutting parameters were selected for drilling simulation, and the chips and their formation reasons were analyzed. Orthogonal test method is selected for drilling processing test. The obtained damage test results such as burr, tearing, delamination damage and hole wall damage are compared with the simulation results to verify and analyze their causes. The results show that when drilling the T300 carbon fiber composite the tear defects at the exit of the hole are much larger than those at the entrance of the hole. That is, the quality of the entrance drilling is better than that of the exit drilling. The largest impact on the exit and the entrance tear value is the diameter of the drill bit, the cutting speed is the second, and the feed rate has the least effect. However, the diameter of the drill bit has the greatest influence on the hole size error, followed by the feed rate, and the cutting speed has the least effect.