By using 5-amino-3-nitro-1，2，4-triazole （ANTA） as raw material， a new methyl-bridged nitrogen-oxygen heterocyclic energetic compound 3-（（5-amino-3-nitro-1H-1，2，4-triazol-1-yl）methyl）-1，2，4-oxadiazol-5-amine （3） was synthesized through a three-step reaction. The reaction conditions， including solvent， reaction temperature， and reaction time， were thoroughly investigated. Compounds 1-3 were characterized by nuclear magnetic resonance （NMR）， fourier-transform infrared spectroscopy （FT-IR） and elemental analysis （EA）. Single crystal X-ray diffraction analysis was also performed on compound 3. The properties of compound 3 were studied by vacuum densitometer， thermogravimetric differential scanning meter and impact/friction sensitivity meter. The theoretical detonation performances of compound 3 were calculated by Gaussian software. Results show that the total yield of compound 3 is 35.4% based on ANTA. The crystal packing of compound 3 belongs to the monoclinic system， space group P2₁/c， and each cell contains four molecules （Z=4） with a large number of intramolecular and intermolecular hydrogen bonds. The density of compound 3 is 1.68 g·cm^-3， the decomposition temperature is 232.2 ℃， the friction sensitivity is above 360 N， and the impact sensitivity is above 40 J. The theoretical detonation velocity and pressure of compound 3 are 7196 m·s^-1 and 22 GPa， respectively， which are better than that of the traditional explosive TNT（D， 6881 m·s^-1； P， 21.3 GPa）.