The reduction of nitrate using intal circulation micro-electrolysis technology (ICE) was investigated. The effect of the reaction time, initial pH, Fe/C ratio, and aeration rate on the nitrate reduction was investigated using a sin-gle factor experiment. Based on the results of the single factor experiment, a response surface methodology (RSM) was applied to optimize the N2 generation selectivity. The effects and interactions of three independent variables were estimated using a Box–Behnken design. Using the RSM analysis, a quadratic polynomial model with optimal conditions at pH=8.8, Fe/C=1:1, and an aeration rate of 30 L·min?1 was developed by means of the regression analysis of the experimental data. Using the RSM optimization, the optimal conditions yielded a N2 generation selectivity of 72.0％, which is in good agreement with experimental result (73.2％± 0.5％) and falls within the 95％confidence interval (IC:66.8％–77.3％) of the model results. This indicates that the model obtained in this study effectively predicts the N2 generation selectivity for nitrate reduction by the ICE process, thus pro-viding a theoretical basis for process design.