In order to rapidly analyze the product quality of 2，6-diamino-3，5-dinitropyrazine-1-oxide （ANPZO） and optimize the synthesis process， high-performance liquid chromatography （HPLC） method was developed to quantitatively analyze the purity of ANPZO. The effects of mobile phase composition， elution mode and detector wavelength on the resolution have been studied. The separation of ANPZO and its intermediate 2，6-diamino-3，5-dinitropyrazine （ANPZ） was accomplished by using C18 analytical column with size of 250×4.6 mm and 5 µm. The initial mobile phase composition was 0.1% trifluoroacetic acid and methanol （95∶5， v/v）. The methanol ratio was increased to 100% from 2 min to 7 min after the sample injection. Gradient elution was performed at a flow rate of 1.0 mL·min^-1， the column oven temperature was set at 30 ℃， and detection wavelength was 425 nm. The validation of the developed methods showed good linearity （R²=0.9996）， repeatability （%Area RSD%=0.30%） over the concentration range of 0.1 mg·mL^-1 to 0.6 mg·mL^-1. The limit of detection（signal/noise=3） and quantitation（signal/noise=10） of ANPZO were found to be 20 ng·g^-1 and 67 ng·g^-1， respectively. Therefore， the reported method is accurate， precise and sensitive， which can be used for the quality control of ANPZO.