To evaluate the environmental carrying capacity of a subsurface wastewater infiltration system (SWIS) and the removal effect of nitrogen, the simulated soil column experiments were performed. After the SWIS was operated for three years with a hydraulic loading of 5 mm d −1 , the results indicated that the total nitrogen (TN) removal rate and the ammonia nitrogen (NH 4 ± -N) removal rate were 74.22%, 99.69%, respectively, for the high pollution load treatment system and 80.45%, 99.72%, respectively, for the low pollution load treatment system (TN concentrations of 80 mg L −1 and 40 mg L −1 for the two treatment systems, respectively). The ratios of the nitrate nitrogen (NO 3 − -N) concentration in the effluent, which satisfied grade III of the Chinese groundwater standard and the maximum international contaminant level of drinking water were 13.33%, 0.00% and 87.87%, 37.43%, respectively. Adopting the 20 mg L −1 of the NO 3 − -N concentration in the soil leachate as the evaluation criterion, the environmental carrying capacity of nitrogen in the SWIS was in a range of 600 kg N ha −1 y −1 to 1200 kg N ha −1 y −1 . [ABSTRACT FROM AUTHOR]