This article mainly reviewed the research progress of bacteria using carbon, nitrogen as co-substrate degrading and decolorizing azo dyes. The results of the comprehensive literature showed that there was a great difference in the efficacy of the bacteria under different co-substrate conditions, such as with single carbon source, single nitrogen source, and composite of carbon and nitrogen sources. The main influencing factors included the type of carbon source, the type of nitrogen source, concentration, composite ratio of carbon and nitrogen source, etc. Among them, the type of carbon and nitrogen sources had the most significant impact. For degradation and decolorization of azo dyes, the performance could be promoted only by providing suitable type of carbon and nitrogen sources. At the same time, under different carbon and nitrogen co-substrate conditions, the bacterial community structure and dominant functional bacteria species differed greatly. Different carbon and nitrogen co-substrates were used as electron donors for azo dye reduction and decolorization, and with significant differences. Finally, the research direction was forecasted. It was considered that suitable carbon and nitrogen sources had great potential for improving the degradation and decolorization efficiency of bacterial flora. On the other hand, the microbiological mechanism of carbon and nitrogen as co-metabolism substrates, the enzymatic mechanisms, the interaction mechanism between functional strains and functional proteins had to be further studied.