Abstract: Research and experiment are conducted on the technologies used in biochemical wastewater treatment to alleviate the influence of oilfield sewage on the environment, fully use waste water, and reduce the use of fresh water. Other systematic processes and technologies are combined to be used in wastewater treatment, which helps to realize the wastewater reinjection in low-permeability oilfields and enables the oilfield wastewater to meet the discharge standard. In view of the problem that the wastewater reinjection in low-permeability does not easily meet the standard, the fine wastewater treatment process, based on biochemical treatment and fine filtration, is experimentally applied to Block Fan41 of Daluhu Oilfield. The wastewater disposed reaches Grade A1 of the standards. To solve the treatment difficulty of polymer-contained wastewater, the biochemical treatment technology is used to reduce the chemical oxygen consumption of wastewater. As a result, the wastewater disposed reaches the environmental protection standard. Lab research and field experiment results show that oilfield wastewater can be treated with biochemical methods as long as favorable microbes are selected and applied.