Abstract: An air dielectric barrier discharge was used to modify the wettability of polytetrafluoroethylene surfaces at atmospheric pressure. The water contact angle before and after modification was measured using a water contact angle tester. The effects of different discharge times, voltages, and gas gaps on the water contact angle of materials are investigated. The voltage-current curves of the apparatus were tested at different voltages and gas gap distances. Simulation software is used to simulate the air dielectric barrier discharge under atmospheric pressure. The electron density and electron temperature under different gas gaps and voltages were analyzed. The mechanism of material surface modification is analyzed. It is shown that with the increase of time, the water contact angle changed from 90 degrees to around 60 degrees, and remained unchanged after 30 seconds. As the voltage increases and the gas gap decreases, the plasma density and temperature increase. Voltage and gas gap can affect the uniformity of dielectric barrier discharge. The water contact angle of processed materials is related to plasma density, plasma temperature, and uniformity. The results of this experiment have reference value for the application of dielectric barrier discharge in various fields.