The textile industry is one of the major industries of Taiwan but unfortunately it produces toxic and low biodegradable wastewater. To remedy this problem, this study compared the performance of the membrane bioreactor (MBR) and sequencing batch reactor (SBR) processes for treating real textile dyeing wastewater. The microbial diversity of the MBR process was also identified by a combination of culturing methods and molecular biotechnology. The removal efficiencies of the MBR process for color, COD, BOD, and SS were 54, 79, 99, and 100%, respectively, all higher than the corresponding parameters for the SBR process: i.e., 51, 70, 96, and 60%. All the above four parameters for the MBR effluent meet the criteria of the Taiwan EPA, while on the other hand, for the SBR process, only color and COD meet the Taiwan EPA effluent criteria. Furthermore, the genus Microbacterium, in particular Microbacterium aurum, was the most predominant population, accounting for 70.6% of the total isolates, and might be responsible for the degradation of the dyeing wastewater. Another two textile dyeing degradation bacteria, Paenibacillus azoreducens and Bacillus sp., were also observed as predominant bacteria in MBR sludge.