3, 4-Diaminofurazan (DAF) was synthesized from glyoxal and hydroxylamine by one step with yield of 48.0% and purity of 99.8%. 3, 3'-Diamino-4, 4'-azoxyfurazan (DAOAF) was successfully obtained through the reaction of DAF and potassium monopersulfate triple salt (KHSO₅·0.5KHSO₄·0.5K₂SO₄) as oxidant in the buffer system of NaHCO₃ solution. Its structure was characterized by IR, ¹H NMR and MS spectra. The purity of DAOAF was determined by HPLC and the impurities contained were also qualitatively and quantitatively analyzed. The optimum synthesis conditions are determined as follows:the molar ratio of n(DAF):n(NaHCO₃):n(KHSO₅·0.5KHSO₄·0.5K₂SO₄) is 1:6:4 for 5 h at 20-25℃, the yield and purity of crude product are 84.1% and 98.2%, respectively. The impurities contained in the crude DAOAF are DAF, DAAF and ANF. The impurities can be removed effectively by recrystallizing from DMF at 95℃, thus producing high-purity DAOAF (99.6%), with a total recovery rate of 86.6%.