2,6-Diamino-3,5-dinitropyridine-1-oxide(ANPyO) was synthesized from nitration of 2,6-diacetamidopyridine-1-oxide(DAPO) with N₂O₅/solvents and N,N,N -trimethyl- N -propanesulfonic acid ammonium hydrogen sulfate (TMPSHSO4) as the nitrating agent and catalyst. The effects of reaction solvent,temperature and time on the yield of ANPyO were studied. The optimal reaction conditions were obtained: reaction solvent is CH₃NO₂; reaction temperature is 60 ℃; reaction time is 5 h; the yield of product is 92.5%. The structure of ANPyO were characterized by ¹H NMR, IR and MS.