Heat-resistant explosives are indispensable compounds in the fields of energy exploitation and aviation. In this study, with 5-nitro-3-trinitromethyl-1,2,4-triazole as the raw material, an energetic metal salt dilithium 5-nitro-3-(dinitromethyl)-1,2,4-triazole (DN-2Li) with high thermal stability was obtained. The application evaluation parameters including thermal stability, mechanical sensitivity, and detonation performance were fully studied. The results show that DN-2Li not only has good detonation performance (D v = 8669 m s −1 , P = 30.2 GPa) but also has appropriate mechanical sensitivity (IS = 4.0 J, FS = 100 N) and excellent thermal stability (T d = 350.0 °C, E K = 235.1 kJ mol −1 ), which fully implies that DN-2Li has high application value as a heat-resistant explosive. This study not only provides a kind of heat-resistant explosive with potential application value but also provides a new vision for the design and preparation of new heat-resistant explosives.