Wastewater containing Cr6+ with large water quantity and high levels of toxicity damages human health through the food chain. Electric flocculation was one of the commonly used methods for heavy metals wastewater treatment, which was applied to remove Cr6+ from wastewater. In this study, response surface methodology (RSM) was used to investigate the effects of different operating conditions on the removal efficiency of Cr6+ by the electric flocculation with iron electrodes. Box-Behnken design (BBD) was used for the optimization of the electric flocculation process to evaluate the effects and interactions of process variables such as initial pH, the electrode distance, the current density, and reaction time on the removal efficiency of Cr6+. The optimum values were found to be 5.48, 2.51 cm, 87.55 A/m(2), and 25.6 min, respectively. Under this condition, the removal efficiency of Cr6+ reached 99.34%.