Abstract: The aramid fiber-reinforced polymer(AFRP) composite are proverbial difficult-to-machining materials, it is easy to generate defects of burr and ablation. At present, there is lacks of the effective processing methods for AFRP composite. In order to raise processing quality, the drilling experiment of AFRP composite using liquid nitrogen as cooling medium was studied. A comparative test of dry cutting and cryogenic machining under the same cutting parameters was carried out. The axial cutting force and temperature in the vicinity of the hole in the cutting process were measured, and the delamination factor and fuzzing area after drilling were calculated. The causes of AFRP composite machining defects were analyzed, and the changing rules of defects under different cutting conditions were discussed. The results show that compared with dry cutting, the cutting force increases by 15.2%, the cutting temperature decreases by 141.6℃, and the burr area decreases by 24.7%. The ablation phenomenon caused by cutting heat is inhibited, visibly improving the processing quality of AFRP composite when liquid nitrogen ultralow temperature cooling is used.