Nitrogen removal and crop growth in a trial soil column wastewater irrigation system are observed,and the impact of increased wastewater organic carbon content on them are tested.It is shown that with the increase of wastewater organic carbon content,the volume of drainage,the amount of leached nitrogen(ammonium,nitrate and total nitrogen) and COD will increase,while the dry matter yield of the crop and the amount of nitrogen uptaken by the crop will decrease.The changed soil circumstance resulted from increased wastewater organic carbon content has a negative impact on crop growth.