3,6-diamino-1,2,4,5-tetrazine (DATZ) was synthesized from 3,6-bis(3,5-dimethyl-pyrazol-1-yl)-1,2,4,5-tetrazine (BT) with a yield of 95.3%,DATZ was oxidized with peroxyformic acid to give a high-nitrogen energetic compound 3,6-diamino-1,2,4,5-tetrazine-1,4-dioxide (DATZO₂) with a yield of 60.2%. The structures of both DATZ and DATZO₂ are identified and characterized by IR,NMR,DSC,MS,elemental analysis and melting point test etc. Moreover,the effects of reaction conditions on the yield of DATZO₂ were studied, and the optimum reaction conditions are DATZ 1.12 g (0.01 mol),methane acid 200 ml and hydrogen peroxide 4 ml, reaction time 1 h and reaction temperature 25 ℃.