Abstract: Plasma treatment of ITO thin film is carried out in a pretreatment chamber to investigate the influences of plasma treatment pressure and treatment time on the wettability and performance parameters of the films under four working gases:oxygen,nitrogen,argon and air. The contact angle tester characterization shows that longer plasma treatment times and higher treatment pressures will result in smaller static H₂O contact angles and higher wettability. The results of the spectrophotometer tests show that the ITO thin film transmittance is reduced after the plasma treatment. Under four working gases,the effect on transmittance decreases as the plasma treatment pressure becomes larger,but increases as the treatment time becomes longer. Compared to other gases,the oxygen plasma treatment has the least overall change. Four-point probe characterization shows that the sheet resistance of the treated ITO thin film does not change significantly;it is because the plasma treatment only modifies the surface of the ITO thin film and does not change its internal properties. Using the Hall effect to measure carrier concentration,it is found that there is no significant change,which is exactly consistent with the conclusion that the sheet resistance is constant.