Abstract: This paper was established a method to analyze the nitrate nitrogen content in soil by ion chromatography.The different sample treating conditions were compared and then an optimized method was built.Soil samples were extracted by 0.01 molL calcium chloride solution in a sampleextraction ratio（VW）of 1∶5 with oscillating water bath for 30min in 20～25℃.Then the nitrate nitrogen was separated by anion exchange chromatography with KOH as elution buffer，and then detected by electrical conductivity detector.The results of accuracy and exactitude experiments showed that this method could be used to determination of nitrate nitrogen in most kinds of soil.