The removal of nitrate by micro-electrolysis process was studied. According to principles of micro-electrolysis, the reaction column was fed with iron filings and granular activated carbon. By controlling pH value, NO3−-N concentration, HRT, aeration, the influence of these factors were investigated. The results showed that when at the case of 1∼2.5 of pH value, 40mg/L of NO3−-N, 90min of HRT,180∼260 of air/water rate, 4∶3 of Fe/C(cubage), 68% denitrification rate was achieved. The pH value and aeration amount has a lager influence on the treatment effect. The removal of nitrate by micro-electrolysis process was effective.