The wastewater characterization, modeling and simulation study is the base of the design wastewater treatment plants (WWTPs). So that this paper investigate analysis and characterization of wastewater nitrogen components for using in wastewater modeling and simulation. The analysis was taken for raw wastewater, and settled wastewater. The wastewater samples source for the present study was a preliminary treated wastewater from Al Qenayat wastewater treatment plant, Zagazig, Egypt. Distillation apparatus used to measure ammonia nitrogen method and total kjeldahl nitrogen (TKN) method. Raw wastewater, ammonia nitrogen percent was 73.5% from TKN, soluble organic nitrogen biologically degradable, SND percent was 8.3% from TKN, soluble organic nitrogen biologically undegradable, SNI percent was 3.4% from TKN, particulate organic nitrogen biologically degradable, XND percent was 6.2% from TKN, particulate organic nitrogen biologically undegradable and XNI percent was 3.4% from TKN. Settled wastewater, ammonia nitrogen percent was 77.2% from TKN, soluble organic nitrogen biologically degradable, SND percent was 8.5% from TKN, soluble organic nitrogen biologically undegradable, SNI percent was 3.8% from TKN, particulate organic nitrogen biologically degradable, XND percent was 6.4% from TKN, particulate organic nitrogen biologically undegradable and XNI percent was 4.1% from TKN.