A high energetic oxidizer N-oxides of 3, 3′-azo-bis(6-amino-1, 2, 4, 5-tetrazine)(DAATO_3.5) was synthesized via the two-step oxidation reactions of potassium permanganate and hydrogen peroxide/trifluoroacetic anhydride, using 3, 6-diamino-1, 2, 4, 5-tetrazine as starting material. The total yield of DAATO_3.5 was 53.1%. Its structure was characterized by FT-IR, NMR and elemental analysis. The reaction mechanism for H₂O₂/ (CF₃CO)₂O oxidation was studied. The optimum conditions of the reaction were determined as: 3, 3′-azo-bis(6-amino-1, 2, 4, 5-tetrazine)(DAAT)/(CF₃CO)₂O/H₂O₂=1/12.5/11 (molar ratio), reaction time, 20 h and reaction temperature, 20~25 ℃. The thermal behavior of DAATO_3.5 was studied by DSC and TG-DTG. Results show that DAATO_3.5 has an exothermic decomposition peak at 254.6 ℃, indicating a better stability. The main properties of DAATO_3.5 was tested and followed as: density 1.840 g·cm^-3, friction sensitivity 100%(90°), impact sensitivity 100%(10 kg, 25 cm).