Coking wastewater is a kind of highly toxic and refractory organic wastewater, and aerobic activated sludge, which is dominated by bacteria, determines the efficiency of coking wastewater treatment. However, the bacterial community structure of activated sludge from coking wastewater has rarely been reported. 454 sequencing technology was applied to investigate the structure and biodiversity of the bacterial community. The results of thermal cluster analysis and principal component analysis demonstrated the differences in biodiversities of different activated sludge bacterial communities. The bacterial communities were mainly composed of Proteobacteria, Planctomycetes, Acidobacteria, Candidatus Saccharibacteria, Bacteroidetes, Cyanobacteria, Actinobacteria, Chloroflexi, Firmicutes, Thaumarchaeota, Ignavibacteriae, Verrucomicrobia and Unclassified bacteria. Proteobacteria was the dominant phylum and its abundance was 36.00%-76.98%. The primary genera were Thiobacillus, Thauera, Comamonas, Caldimonas, Steroidobacter, Nitrosomonas, Phycisphaera and Gp4. Most of these genera were related with aromatic hydrocarbon degradation, nitrification and denitrification processes. These results provide a theoretical basis for removal mechanism of pollutants in coking wastewater.