Abstract: With the development of oil production technology, air injection technology has been paid much attention by many domestic and foreign oil fields, but the oxygen in the air will cause serious corrosion problems to oil pipeline and other equipment. In order to make clear the main corrosion factors, corrosion law, corrosion mechanism of air injection, we have conducted corrosion tests of 20^# and L360 by using high temperature and high pressure reactor to simulate the working conditions. The morphology and products of corroded samples are characterized and analyzed by metallographic microscope and X-ray diffractometer, the corrosion law and mechanism of different oxygen content, pressure and temperature are studied. The corrosion rate increases with the increase of oxygen content, pressure and temperature. Metallographic observation shows that pitting corrosion and ulcer corrosion are the main corrosion types, and XRD analysis shows that the main components of the corrosion products are iron oxides. To sum up, the leading factor of corrosion is oxygen content, and the oxygen content of injected air should be properly controlled in the production of oil field.