A novel micro-electrolysis reactor bringing iron-carbon filler to cycle flow was developed in this study, called as an internal circulation micro-electrolysis (ICE) reactor, which can overcome the disadvantage of conventional fixed bed (CFB) reactor. In order to investigate the performance of the ICE reactor, a practical dyes wastewater was selected as target wastewater. The removal efficiency of chemical oxygen demand (COD) and chroma of the CFB reactor with commercial hardening resistance iron-carbon filler (CRIF) are only 23% and 40%, respectively. However, for the ICE reactor with a common iron-carbon mixture (CIM), the removal efficiency of COD and chroma are 73% and 98.5%, respectively. The improvement efficiency of biodegradability index of dyes wastewater for the ICE reactor with the CIM is 23 times, which is about fourfold as much as that of the CFB reactor with CRIF. The ICE reactor with CIM can stably keep a high treatment performance for 60 days continuous operation. However, the performance of CFB reactor with CIM decreases sharply. The results indicate that the ICE reactor has an excellent performance for the pretreatment of dyes wastewater, which should be due to the elimination of hardening, blocking and inactivation occurring in the CFB reactor with CIM by the circulation action. (C) 2016 Elsevier B.V. All rights reserved.