A new method using high-performance liquid chromatography was developed to measure nitrite and nitrate levels in vegetables. The method can detect nitrite and nitrate in vegetables at concentrations ranging from 0 to 80 mg/kg, with high accuracy and sensitivity. The results showed that the method is simple to use, more sensitive, and faster compared to the current standard method in China. The recovery rates for nitrite and nitrate were high, and the method showed low variability in results.