The main goal of a series of laboratory experiments was to determine the efficiency of iron for removing hexavalent chromium. The results indicate that the reductive reaction of zero_valent iron with hexavalent chromium reaches the quasi_ first_order standard, that the ratio of the granular iron (BTE 2.89 m 2/g) to solution increases from 0.5 g/100 mL to 2.0 g/100 mL, and that the reaction time is reduced from 26.7 min to 3.6 min. It is also shown that the reaction time should be prolonged to meet the standard of drinking water because the concentration of initial solution within 30 mg/L increases when the quantity of iron is stable, and that the raising of the temperature promotes the removal of hexavalent chromium when other conditions are constant.