In this study, petroleum refinery wastewater was treated by an electrochemical process with three-dimensional multi-phase electrode, which introduced Fe particle and air into a traditional two-dimensional reactor. The effect of Fe particle and air on the electrochemical process, and the optimal experimental conditions including initial pH, cell voltage were investigated. The experimental results showed that the effluent with a satisfied COD removal efficiency (92.8%) and low salinity (84 mu S cm(-1)) was obtained when the initial pH was 6.5, cell voltage was 12 V and fine Fe particle was introduced. This result can be also supported by the analysis of GC-MS. UV spectrum and Conductivity. Moreover, the possible reaction mechanism of this process was discussed by comparing the results of variant reaction systems with different metal particles. All of these results suggested that the electrochemical system with three-dimensional multi-phase electrode was an effective approach to treat petroleum refinery wastewater. (C) 2011 Elsevier B.V. All rights reserved.