An experimental study on in-site remediation of groundwater polluted by NO3-N was carried out by combining artificial nitrogen-removing bacteria with CH3CH2OH,CH3COONa,C6H12O6 and white sugar.The results show that when using CH3CH2OH and CH3COONa as carbon sources,NO-3N in groundwater can be effectively eliminated.However,due to the low seepage flow speed of groundwater,added substances often fail to completely mix with groundwater,which results in only a small quantity of decontaminated groundwater. For this,the following measures can be taken: Artificially pumping and injecting water in the range from the center of polluted area to its border;Continually adding the carbon source in certain proportion during injecting water;Intermittently adding artificial nitrogen-removing bacteria.The mixing of added nutrient substances with groundwater is greatly improved after these measures are adopted,and the pollutant removal process consequently becomes more effective.