Abstract：Trichloroethylene (TCE) has become a major soil and groundwater contaminant in many countries, and we are facing a great challenge to repair it, due to its toxicity and persistence in the environment. In addition, the TCE contamination usually exists with aromatic compounds in the contaminated site. In most cases, benzoic acid has been shown to be the metabolic intermediate of benzene and most of aromatic compounds under anaerobic conditions. In our study, anaerobic enrichment cultures which were fed with TCE along with benzoate as the sole carbon source and electron donor were constructed and will be studied further. We plan to explore the key members in the anaerobic consortia by using the technology of DNA-SIP and high-throughput sequencing. Afterwards, we will design the primers for different key members according to the sequences information, and then use reverse transcript-qPCR to confirm the physiological ability of them. From all the results we obtained, we hope we can elucidate the anaerobic reductive dechlorination mechanism under the combined contamination of benzoic acid and TCE. The accomplishment of this project will develop our insights into the degradation mechanisms to combined pollution of TCE, and also will give some advice to bioremediation of multiple contamination.