From the fields of a long-term (since 2005) experiment on integrated water and nitrogen management in Fengqiu National Agro-ecological Experiment Station, samples were taken of the soils in the cultivated layers (0~10 cm, 10~20 cm and 0~20 cm) of fields under different patterns of integrated water and nitrogen management after the harvest of summer maize in September, 2011 for analysis of six forms of nitrogen, i.e. inorganic nitrogen (IN), organic nitrogen (ON), dissolved organic nitrogen (DON), acidolytic organic nitrogen (AON), acidolytic ammonium nitrogen (AAN), microbial biomass nitrogen (MBN), and three biological indices that are closely related to N turnover, i.e. urease activity (URE), protease activity (PRO) and nitrification potential (NP). Three-way ANOVA of the analytic results indicate that both nitrogen fertilization and topsoil depth had significant effects on the six forms of nitrogen, but irrigation had none. One-way ANOVA shows that nitrogen fertilization significantly increased soil IN, ON, URE and NP in the 0~20 cm topsoil, but had no such effect on soil AON and AAN and volume of irrigation had nothing to do with the six forms of nitrogen, PRO and NP. Regardless of patterns of integrated water and nitrogen management, the six forms of nitrogen, URE, PRO and NP were almost all considerably higher in the 0~10 cm topsoil than in the 10~20 cm topsoil. Through the experiment, it is found that irrigation to meet the field water-holding capacity in the 0~20 cm soil layer and nitrogen fertilization at a rate of 190 kg hm^-2 per crop season is the optimal patterns of integrated water and nitrogen management.