Abstract: The total DNA was directly extracted from the oil wastewater of Shuguang Wastewater Treatment Plant in Liaohe Oilfield, and by the methods of PCR-DGGE and conventional water quality analysis, the relationships between the bacterial diversity in the wastewater during its treatment process and the water quality were analyzed. There were significant differences in the bacterial communities at different treatment stages, not only some common bacterial species, but also the unique bacteria population. The bacterial diversity was negatively correlated with the CODcr and TPH concentrations in wastewater. The higher the CODcr and TPH concentrations, the lower the bacterial diversity was. During treatment process, the similarity coefficient (C_s) of bacterial communities in the wastewater increased with enhancing bacterial diversity, and finally formed a stable population structure.

Key words: Soil microbial biomass, Soil enzyme activity, Fertilization