An ion chromatography method with suppressed conductivity for determination of nitrate nitrogen (NO-3N)in watersoluble fertilizers containing nitrogen，phosphorus and potassium was developed.Under optimized chromatographic conditions，NO-3 was well separated from other anions commonly found in watersoluble fertilizers.The result showed that the calibration curve was linear in the range of 0~20 mg/L (R2=0.999 9)．The limit of detection(LOD)was 0.007 mg/L.The recoveries were ranged from 98.52% to 102.10% (RSD= 0.54%，n=7).The results were compared with those by the standard NY/T 1116-2014.It showed that there was no significant difference between the two methods.The established method with no interference is stable，reliable and efficient，and can be applied to the analysis of large batches of watersoluble fertilizer samples.