Abstract: Vacuum reactive evaporation coating technology was used to deposit AlO_x+Al+AlO_x on the surface of PET(polyethylene terephthalate).It improves the traditional evaporative coating equipment,and a uniform gas pipe was introduced to control the oxygen inlet position and flow rate.The influence of oxygen flow rate on film morphology,binding force,and barrier properties during reactive evaporation was studied.SEM,EDS,3M standard tape,and oxygen permeator were used to characterize thin films.The results show that the AlO_x+Al+AlO_x/PET composite film can effectively improve the barrier properties,compactness,and binding force between the coating and the film.The AlO_x+Al+AlO_x/PET composite film was vapor-deposited under the background vacuum of 8×10^-4Pa,reaction pressure of 1×10^-2Pa,current of 80 A,transition layer oxygen flow rate of 50 m L/min,cap layer inflation flow rate of 100 mL/min.The binding force between film layers was 1.52 N/mm,and the oxygen transmission rate was 1.1 cm³/(m²·day·atm).Compared with the traditional aluminum film,the binding force was increased by 2 times,and the barrier property was increased by 4.5 times.