Coolant for heavy duty engine containing nitrite could prevent cavitation corrosion of diesel cylinder liners. In this paper, 850 Profession chromatograph was used to determine the content of NO2- in heavy load antifreeze, as well as adopting A4-250 ion analysis column, leacheate with concentration of 1.8 mmol / L Na2CO3 and 1.7 mmol / L NaHCO3, and conductivity detector. As a result, average value of the sample was tested as 492.7 ppm with 10 times repeated measurements, repeatability error of the maximum and the mean was 1.3%, repeatability error of the minimum and the mean was 1.9%, which was lower than national standrads that the repeated requirement for nitrite ions teasted in ion chromatography method was ≤5.2%. The results showed that this method had advantages of simple operation and high accuracy.