1-Amino-3-methyl-1, 2, 3-triazolium nitrate(1-AMTN) was synthesized using glyoxal and hydrazine hydrate as starting materials in three steps, i.e. addition-elimination, cyclization, methylation and replacement reaction. The overall yield is 71.8%(based on glyoxal). The structure of products was confirmed by IR, MS, NMR and elemental analysis. The properties of 1-AMTN were estimated: density 1.63 g·cm^-3, enthalpy of formation 84 kJ·mol^-1 and detonation velocity 8115 m·s^-1. The key factors of cyclization and methylation were studied and the optimal reaction conditions were confirmed: medium acetonitrile, 20 ℃, and the ratio of glyoxal bishydrazone and methyl Iodide 1:5. The overall yield of cyclization and methylation is 86.7%. In addition, actived manganese oxide was recycled and its mechanism was also discussed.