This paper introduces the determination method of total nitrogen content containing fertilizers,includes identifying nitrogen forms in unknown samples,selecting appropriate pre-processing technique,convert other forms of nitrogen into ammonium nitrogen,and distillation with semiautomatic determination of nitrogen analyzer.Compared with corrent national standards,this method has advantages of simple operation,small reagent dosage,high accuracy,and precision.It's adapted to the analysis of sample in mass,and deserves application in fertilizer analysis.