Electrochemical oxidation of ammonia in an undivided cell was studied in the present experiments. The optimization of the influencing factors on electrochemical removal of ammonia by response surface methodology (RSM) was also studied. Ammonia could be effectively removed by electrochemical method, and which was mainly oxidized into harmless nitrogen gas. The Box-Behnken design can be employed to develop mathematical models for predicting electrochemical ammonia removal geometry. The desired electrochemical ammonia removal can be achieved by choosing the predicted conditions using the developed models. In the present experiments, the optimal NaCl dosage, current density and electrolysis time are 0.31 g/L, 42.75 mA/cm(2), and 100.64 min, respectively, at which the ammonia-N and nitrate-N concentration in the treated solution are 0 and 1.1 mg/L, respectively, which will meet the standards for drinking water. (C) 2011 Elsevier B.V. All rights reserved.