5，7-Diamino-8-nitrotetrazolo［1，5-c］pyrimidine （3） was synthesized by a two-step reaction of nitration and cycloaddition using 2，4-diamino-6-chloropyrimidine （1） as raw material. The structure of 3 was characterized by nuclear magnetic resonance spectrometer （NMR）， Fourier transform infrared spectrometer （FT-IR）， elemental analyzer （EA） and single crystal X-ray diffractometer （SC-XRD）. The thermal behavior of 3 was analyzed by differential scanning calorimeter （DSC） and thermogravimetric （TG）. The detonation properties were calculated by Gaussian and Explo5. The sensitivities were measured using BAM impact and friction sensitivity testers. The results show that the crystal of compound 3·DMSO belongs to monoclinic system， space group P2₁/c， and the cell parameters are a=4.7331（3） ?， b=22.8991（13） ?， c=10.6580（6） ?， α=90°， β=99.758（2）°， γ=90°， V=1138.44（12） ?³， Z=4. The crystal density is 1.600 g·cm^-3 （296 K）. The theoretical detonation velocity and pressure of 3 are 8570 m·s^-1 and 28.2 GPa， respectively. The impact and friction sensitivities of 3 are 22 J and 305 N， respectively.