Starting from 5-amino-3-nitro-1,2,4-triazole (ANTA), a new type of energetic compound with a methyl-bridged nitrogen-oxygen heterocyclic ring, the methylene bridging compound 3-((5-amino-3-nitro-1H-1,2,4-triazol-1-yl)methyl)-1,2,4-oxadiazol-5-amine (3), has been synthesized through a three-step reaction. The reaction conditions, including appropriate solvent selection, reaction temperature, and reaction time, were thoroughly investigated and the total yield of 3 was 35.4% based on ANTA. 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 properties of compound 3 were studied by Gaussian software. The results show that the crystal packing of compound 3 belongs to the P21/c monoclinic crystal system, each cell contains four compound 3 molecules (Z = 4), and there are 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 °C, the friction sensitivity is >360 J, and the impact sensitivity is>40 J. The theoretical detonation velocity D is 7196 m·s-1, and the detonation pressure P is 22 GPa, which is better than the traditional explosive TNT (D, 6881 m·s-1; P, 21.3 GPa).