Anaerobic biological process has been applied for the treatment of purified terephthalic acid (PTA) wastewater containing complex aromatic compounds; however, the performance of the treatment has significant potential for greater efficiency if the limited knowledge of metabolic capacity and interaction of anaerobic microbes in these systems is deepened. In this study, we perform microbial community profiling of seven full-scale and three lab-scale anaerobic bioreactors treating PTA wastewater by using 16S rRNA gene amplicon sequencing approach to elucidate the co-occurrence network patterns of dominant microbial constituents, including syntrophic substrate oxidizing bacteria, methanogenic archaea, and functionally unknown organisms in the systems.