Abstract: A carbon fiber reinforced plastics (CFRP) composite was drilled by twist drill and three flutes twist drill, and the effects of structure and point angle of drill on drilling thrust and roughness of inter wall of holes were studied. The results show that the more of the point angle of twist drill, the large of the drilling thrust, and increasing the point angle of three flutes twist drill had not obviously effects on drill thrust. The volatility of the drilling thrust caused by the tool′s torsion and vibration of the three flutes twist drill obviously less than that of the twist drill, and the roughness of inter wall of holes mechined by the form less than that of the later. The roughness of inter wall of holes mechined by the two drills obviously decreased with the increase of the point angles.