Starting from (1-tert-butyl-3-nitroazetidin-3-yl)methanol, a melt-cast explosive of 3-azido-1,3-dinitroazetidine (AzDNAZ) with novel gem-azidonitro energetic group was obtained through an improved azidation-salinization-nitration strategy with a total yield of 58.8%. Structures of the intermediates and AzDNAZ were characterized by ¹H NMR, ¹³C NMR, IR and element analysis. One of the intermediates, 1-t-butyl-3-azido-3-nitro-azetidinium nitrate (compound 2), was obtained for the first time with the single crystal determined by X-ray single crystal diffraction, which reveals that it crystallizes in monoclinic, space group P2(1)/n with a=0.8281(314) nm, b=0.8607(2) nm,c=1.7195(2) nm, α=90°, β=94.983(2)°,γ=90°,V=1.2210(6) nm³,Z=4, M_r=262, D_c=1.427 g·cm^-3, μ=0.174 mm^-1, F(000)=552, R=0.0418 and ωR=0.1168. Meanwhile, thermal behaviors of AzDNAZ were studied by subsequently differential scanning calorimetry (DSC) and thermal gravimetric analyzer (TG) methods. Based on the measured values of density and heat of formation, the detonation parameters were calculated by Gaussian 09 program and Kamlet-Jacobs equations. Results show that the melting point, decomposition point, density, heat of formation, detonation velocity and detonation pressure are 78.2 ℃, 180.7 ℃, 1.75 g·cm^-3,331.73 kJ·mol^-1, 8460 m·s^-1 and 31.83 GPa, respectively, indicating AzDNAZ can be applied as a promising melt-cast explosive or an energetic plasticizer with satisfactory performances.