Abstract: Using H2SO4, H2C2O4 and C7H6O6S · 2H2O as basic electrolyte with 0, 5, 15 and 25 mL/L PTFE emulsion taken as additives separately, the hard Al2O3-PTFE composite films were prepared on the surface of 2024 aluminum alloy. The structure, performance and formation mechanism of the composite films were studied by SEM, hardometer and tribo-wearometer. The result showed that the film sample thickness is 42 μm without PTFE added in, and it increases to 51 μm with PTFE added increasingly. The hardness tends to increase then decrease, and biggest hardness is 417 HV. When the concentration of added PTFE is 25 mL/L, the wear loss is 7 mg, i.e. about one third of that without PTFE added. The PTFE contained in the oxide film will form a lubricating layer when it is in contact with a frictional part, thus decreasing the friction coefficient to improve the wearability and self-lubricating performance of the anodizing film with its hardness kept up.