This study investigated effective operating method of enhanced electrokinetic-Fenton (EK-Fenton) process with anionic surfactant to remediate contaminated iron-rich clayey soil with phenanthrene, which had soil properties being frequently in contaminated sites. Introduction of 30 mM SDS as H2O2 stabilizer improved not only H2O2 stability but also degradation of phenanthrene compared to experiment without SDS. However, electrical potential drop in regions near cathode terminated electro-osmotic flow, and then phenanthrene in region near cathode kept initial concentration before switching of the electrodes polarities and introduction direction of reagents. After the polarity of the electrodes and introduction direction of reagents were switched, electro-osmotic flow was re-generated with re-distribution of electrical potential and electrical current. Furthermore, after switching electrode, decrease of iron concentration and pH in the soil specimen near cathode before switching electrode generated decrease of H2O2 decomposition rate. Therefore, H2O2 could be introduced in the cathode regions before switching the polarity of the electrodes and introduction direction of reagents. Furthermore, residual phenanthrene was degraded homogeneously after switching of the electrodes polarity and introduction direction of reagents, and then about 70% phenanthrene could be degraded. (C) 2011 Elsevier Ltd. All rights reserved.