In order to develop the peripheral part of Daqing oilfield, one mixed bacteria system was screened and used for microbial flooding on Microbial Enhanced Oil Recovery (MEOR) process in Daqing low permeability oilfield where there are huge resource potentials but many disadvantageous conditions. From 2004 to 2009, Microbial flooding field test was conducted in Chaoyanggou oilfield. In 2004, Microbial flooding pilot test with 2 injectors and 10 producers was carried out. Seven out of 10 oil wells showed effective results, with 14.5 thousand tons of accumulative incremental oil. In October 2009, expanding field test with 9 injectors and 24 producers was carried out in the same block. By now, 15 oil wells have shown good effect. The daily oil production increased from 32.4 tons to 43.2 tons and the incremental oil amounts to 9370 tons. The microbial flooding results showed that wells along the main channel sand and developed fracture zones had a better response.