Azo dyes are toxic, highly persistent, and ubiquitously distributed in the environment.A large quantity of dye wastewater was produced when they are widely used in the textile industry, which are required tobe decolorated before discharged.In this study, anew BES was designed to remove azo dyes in cathode zone andoxidantorganic electron donor in anode zone.This reactor is a membrane-free and continuous feeding up-flow biocatalyzed electrolysis reactor (UBER),placing a cathode zone downside and anode zone upside.