Abstract: To better the field application effect of facultative anaerobic biological flooding under extremely high temperature, pressure and anaerobic oil reservoir, experiments were conducted to optimize the facultative anaerobic microorganisms. Study was conducted from both simulated ferment system and physical analogue experiments, to optimize the metaboly and oil driving capacity of the bacteria under aerobic circumstance. The study shows that the concentration of thalli and metabolic product is obviously higher under modesty aerobic circumstance than that of anaerobic circumstances. When the oxygen concentration was about 4.0 mg/L, the culture solution could reach the logarithm vegetation period with the shortest time. By further experiments, the optimum oxygen concentration was ascertained to be 4.2 mg/L for BS36 bacteria. The core flooding experiment also showed that air assisted microbial flooding could improve the recovery rate over single MEOR by 5.5%. The field tests also testified that this new technology could improve the recovery rate over single MEOR.