Using sodium 5-nitrotetrazolate dihydrate as starting material, 2-dinitromethyl-5-nitrotetrazole (HDNMNT) was synthesized via the reactions of substitution and nitration-hydrolysis with a total yield of 51.89%. The structure of HDNMNT was characterized by means of ¹H NMR, ¹³C NMR, Fourier Transform Infrared Spectroscopy(FTIR) and elemental analysis. In order to study the performance of HDNMNT, the density, enthalpy of formation and detonation parameters were calculated theoretically, the thermal stability was analyzed by the differential scanning calorimetry(DSC) method. Results show that the density of HDNMNT is up to 1.880 g·cm^-3, the enthalpy of formation is 273.0 kJ·mol^-1, and the detonation velocity and detonation pressure are 8.732 km·s^-1 and 35.4 GPa, respectively, which can be camparative with RDX. However, the decomposition temperature of HDNMNT is only 120 ℃, showing a relatively poor thermal stability.